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197 | Before you begin
Usage notes for NAT rules:
• You can include the round-robin keyword, but you cannot include extended, flat, include-reserve, or
interface (for interface PAT fallback). Other source/destination address and port information is also
allowed.
• As with all NAT changes, if you replace an existing rule, you... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
198 | object network mapped-pat-pool
range 10.100.10.1 10.100.10.2
object network src_network
subnet 10.100.10.0 255.255.255.0
nat (inside,outside) 1 source dynamic src_network
pat-pool mapped-pat-pool block-allocation
Configure Per-Session PAT or Multi-Session PAT
By default, all TCP PAT traffic and all UDP DNS traffic uses... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
199 | xlate per-session deny udp any6 any4 eq domain
xlate per-session deny udp any6 any6 eq domain
Procedure
Create a permit or deny per-session PAT rule. This rule is placed above the default rules, but below any other
manually-created rules. Be sure to create your rules in the order you want them applied.
xlate per-sessio... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
200 | Static NAT
The following topics explain static NAT and how to implement it.
About Static NAT
Static NAT creates a fixed translation of a real address to a mapped address. Because the mapped address is
the same for each consecutive connection, static NAT allows bidirectional connection initiation, both to and
from the h... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
201 | Static NAT-with-port-translation rules limit access to the destination IP address for the specified port only.
If you try to accessthe destination IPaddress on a different port not covered by a NAT rule, then the connection
is blocked. In addition, for twice NAT, traffic that does not match the source IP address of the... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
202 | Figure 22: One-to-Many Static NAT
For example, you have a load balancer at 10.1.2.27. Depending on the URL requested, it redirects traffic to
the correct web server. For details on how to configure this example, see Inside Load Balancer with Multiple
Mapped Addresses (Static NAT, One-to-Many), on page 200.
Figure 23: O... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
203 | the next mapped address is mapped to the first real address, and so on until all mapped addresses are mapped
(A to 4, B to 5, C to 6). This results in multiple mapped addresses for each real address. Just like a one-to-many
configuration, only the first mappings are bidirectional; subsequent mappings allow traffic to b... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
204 | Procedure
Step 1 (Optional.) Create a network object (object network command), or a network object group (object-group
network command), for the mapped addresses.
• Instead of using an object, you can configure an inline address or specify the interface address (for static
NAT-with-port-translation).
• If you use an ob... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
205 | 10.1.1.6, and you specify 172.20.1.1 as the mapped address, then the mapped range will include
172.20.1.1 through 172.20.1.6. For NAT46 or NAT66 translations, this can be an IPv6 network
address.
• mapped_obj—An existing network object or group. To do a one-to-one mapping for a range of IP
addresses, select an object t... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
206 | hostname(config-network-object)# host 10.1.1.1
hostname(config-network-object)# nat (inside,outside) static my-mapped-obj
The following example configures static NAT-with-port-translation for 10.1.1.1 at TCP port 21 to
the outside interface at port 2121.
hostname(config)# object network my-ftp-server
hostname(config-ne... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
207 | • Source or Destination mapped ports
A service object can contain both a source and destination port; however, you should specify either the source
or the destination port for both service objects. You should only specify both the source and destination ports
if your application uses a fixed source port (such as some D... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
208 | destination ports in the object, the first service object contains the real source port/mapped destination
port; the second service object contains the mapped source port/real destination port. For identity port
translation,simply use the same service object for both the real and mapped ports(source and/or destination
... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
209 | The following example shows a static translation of one IPv6 network to another IPv6 when accessing
an IPv6 network, and the dynamic PAT translation to an IPv4 PAT pool when accessing the IPv4
network:
hostname(config)# object network INSIDE_NW
hostname(config-network-object)# subnet 2001:DB8:AAAA::/96
hostname(config)... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
210 | Procedure
Step 1 (Optional.) Create a network object (object network command), or a network object group (object-group
network command), for the mapped addresses.
• Instead of using an object, you can configure an inline address.
• If you use an object, the object must match the real addresses you want to translate.
St... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
211 | • No Proxy ARP—(Optional.) Specify no-proxy-arp to disable proxy ARP for incoming packets to the
mapped IPaddresses.For information on the conditions which might require the disabling of proxy ARP,
see Mapped Addresses and Routing, on page 208.
• Route lookup—(Routed mode only; interfaces specified.) Specify route-look... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
212 | • The mapped object or group can contain a host, range, or subnet.
• The real and mapped source objects must match. You can use the same object for both, or you can create
separate objects that contain the same IP addresses.
Step 2 (Optional.) Create service objects for the:
• Source or Destination real ports
• Source ... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
213 | translation,simply use the same service object for both the real and mapped ports(source and/or destination
ports, depending on your configuration).
• No Proxy ARP—(Optional.) Specify no-proxy-arp to disable proxy ARP for incoming packets to the
mapped IP addresses. See Mapped Addresses and Routing, on page 208 for mor... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
214 | History for NAT
Description
Platform
Feature Name Releases
Configures NAT for a network object IP address(es).
We introduced or modified the following commands: nat
(object network configuration mode), show nat, show xlate,
show nat pool.
Network Object NAT 8.3(1)
Twice NAT lets you identify both the source and destina... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
215 | Description
Platform
Feature Name Releases
You can now specify a pool of PAT addresses instead of a
single address. You can also optionally enable round-robin
assignment of PAT addresses instead of first using all ports on
a PAT address before using the next address in the pool. These
features help prevent a large numb... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
216 | Description
Platform
Feature Name Releases
In rare situations, you might want to use a VPN peer’s real IP
address on the inside network instead of an assigned local IP
address. Normally with VPN, the peer is given an assigned
local IP address to access the inside network. However, you
might want to translate the local ... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
217 | Description
Platform
Feature Name Releases
The per-session PAT feature improves the scalability of PAT
and, for clustering, allows each member unit to own PAT
connections; multi-session PAT connections have to be
forwarded to and owned by the control unit. At the end of a
per-session PAT session, the ASA sends a reset ... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
218 | CHAPTER 9
NAT Examples and Reference
The following topics provide examples for configuring NAT, plus information on advanced configuration
and troubleshooting.
• Examples for Network Object NAT, on page 197
• Examples for Twice NAT, on page 202
• NAT in Routed and Transparent Mode, on page 206
• Routing NAT Packets, on... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
219 | Figure 27: Static NAT for an Inside Web Server
Procedure
Step 1 Create a network object for the internal web server.
hostname(config)# object network myWebServ
hostname(config-network-object)# host 10.1.2.27
Step 2 Configure static NAT for the object:
hostname(config-network-object)# nat (inside,outside) static 209.165... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
220 | Figure 28: Dynamic NAT for Inside, Static NAT for Outside Web Server
Procedure
Step 1 Create a network object for the dynamic NAT pool to which you want to translate the inside addresses.
hostname(config)# object network myNatPool
hostname(config-network-object)# range 209.165.201.20 209.165.201.30
Step 2 Create a netw... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
221 | hostname(config-network-object)# nat (outside,inside) static 10.1.2.20
Inside Load Balancer with Multiple Mapped Addresses (Static NAT,
One-to-Many)
The following example shows an inside load balancer that is translated to multiple IP addresses. When an
outside host accesses one of the mapped IP addresses, it is untran... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
222 | hostname(config)# object network myLBHost
hostname(config-network-object)# host 10.1.2.27
Step 3 Configure static NAT for the load balancer applying the range object.
hostname(config-network-object)# nat (inside,outside) static myPublicIPs
Single Address for FTP, HTTP, and SMTP (Static NAT-with-Port-Translation)
The fo... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
223 | hostname(config)# object network FTP_SERVER
hostname(config-network-object)# host 10.1.2.27
hostname(config-network-object)# nat (inside,outside) static 209.165.201.3 service tcp ftp
ftp
Step 2 Create a network object for the HTTP server and configure static NAT with port translation, mapping the
HTTP port to itself.
h... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
224 | Figure 31: Twice NAT with Different Destination Addresses
Procedure
Step 1 Add a network object for the inside network:
hostname(config)# object network myInsideNetwork
hostname(config-network-object)# subnet 10.1.2.0 255.255.255.0
Step 2 Add a network object for the DMZ network 1:
hostname(config)# object network DMZn... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
225 | Step 5 Add a network object for the DMZ network 2:
hostname(config)# object network DMZnetwork2
hostname(config-network-object)# subnet 209.165.200.224 255.255.255.224
Step 6 Add a network object for the PAT address:
hostname(config)# object network PATaddress2
hostname(config-network-object)# host 209.165.202.130
Step... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
226 | Procedure
Step 1 Add a network object for the inside network:
hostname(config)# object network myInsideNetwork
hostname(config-network-object)# subnet 10.1.2.0 255.255.255.0
Step 2 Add a network object for the Telnet/Web server:
hostname(config)# object network TelnetWebServer
hostname(config-network-object)# host 209.... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
227 | NAT in Routed and Transparent Mode
You can configure NAT in both routed and transparent firewall mode. The following sections describe typical
usage for each firewall mode.
NAT in Routed Mode
The following figure shows a typical NAT example in routed mode, with a private network on the inside.
Figure 33: NAT Example: R... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
228 | • ARP inspection is not supported. Moreover, if for some reason a host on one side of the ASA sends an
ARP request to a host on the other side of the ASA, and the initiating host real address is mapped to a
different address on the same subnet, then the real address remains visible in the ARP request.
• Translating bet... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
229 | Routing NAT Packets
The ASA needs to be the destination for any packets sent to the mapped address. The ASA also needs to
determine the egressinterface for any packetsit receives destined for mapped addresses. Thissection describes
how the ASA handles accepting and delivering packets with NAT.
Mapped Addresses and Rout... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
230 | For transparent mode, if the real host is directly-connected, configure the static route on the upstream router
to point to the ASA: specify the bridge group IP address. For remote hosts in transparent mode, in the static
route on the upstream router, you can alternatively specify the downstream router IP address.
The ... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
231 | Figure 36: Proxy ARP and Virtual Telnet
Transparent Mode Routing Requirements for Remote Networks
When you use NAT in transparent mode, some types of traffic require static routes.See the general operations
configuration guide for more information.
Determining the Egress Interface
When you use NAT and the ASA receives ... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
232 | Figure 37: Routed Mode Egress Interface Selection with NAT
NAT for VPN
The following topics explain NAT usage with the various types of VPN.
NAT and Remote Access VPN
The following figure shows both an inside server (10.1.1.6) and a VPN client (209.165.201.10) accessing the
Internet. Unless you configure split tunnelin... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
233 | Figure 38: Interface PAT for Internet-Bound VPN Traffic (Intra-Interface)
The following figure shows a VPN client that wants to access an inside mail server. Because the ASA expects
traffic between the inside network and any outside network to match the interface PAT rule you set up for
Internet access, traffic from th... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
234 | Figure 39: Identity NAT for VPN Clients
See the following sample NAT configuration for the above network:
! Enable hairpin for non-split-tunneled VPN client traffic:
same-security-traffic permit intra-interface
! Identify local VPN network, & perform object interface PAT when going to Internet:
object network vpn_local... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
235 | Jose), you do not want to perform NAT; you need to exempt that traffic by creating an identity NAT rule.
Identity NAT simply translates an address to the same address.
Figure 40: Interface PAT and Identity NAT for Site-to-Site VPN
The following figure shows a VPN client connected to Firewall1 (Boulder), with a Telnet r... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
236 | ! Enable hairpin for VPN client traffic:
same-security-traffic permit intra-interface
! Identify local VPN network, & perform object interface PAT when going to Internet:
object network vpn_local
subnet 10.3.3.0 255.255.255.0
nat (outside,outside) dynamic interface
! Identify inside Boulder network, & perform object in... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
237 | NAT and VPN Management Access
When using VPN, you can allow management accessto an interface other than the one from which you entered
the ASA (see the management-access command). For example, if you enter the ASA from the outside
interface, the management-access feature lets you connect to the inside interface using A... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
238 | object network vpn_local
subnet 10.3.3.0 255.255.255.0
nat (outside,outside) dynamic interface
! Identify inside network, & perform object interface PAT when going to Internet:
object network inside_nw
subnet 10.1.1.0 255.255.255.0
nat (inside,outside) dynamic interface
! Use twice NAT to pass traffic between the insid... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
239 | • NAT66—TranslatesIPv6 packetsto a different IPv6 address. We recommend using static NAT. Although
you can use dynamic NAT or PAT, IPv6 addresses are in such large supply, you do not have to use
dynamic NAT.
NAT64 and NAT 46 are possible on standard routed interfaces only. NAT66 is possible on both routed and
bridge gr... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
240 | In this example, you translate the inside IPv6 network to IPv4 using dynamic interfacePAT with the IPaddress
of the outside interface. Outside IPv4 traffic is statically translated to addresses on the 2001:db8::/96 network,
allowing transmission on the inside network.
Procedure
Step 1 Create a network object for the in... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
241 | allowing transmission on the inside network. You enable DNSrewrite on the NAT46 rule, so that replies from
the external DNSserver can be converted from A (IPv4) to AAAA (IPv6) records, and the addresses converted
from IPv4 to IPv6.
Following is a typicalsequence for a web request where a client at 2001:DB8::100 on the ... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
242 | With this rule, any IPv4 address on the outside network coming to the inside interface is translated to an
address on the 2001:db8::/96 network using the embedded IPv4 address method. In addition, DNS responses
are converted from A (IPv4) to AAAA (IPv6) records, and the addresses converted from IPv4 to IPv6.
NAT66: Tra... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
243 | hostname(config-network-object)# nat(inside,outside) static 2001:db8:122:2999::/96
With this rule, any traffic from the 2001:db8:122:2091::/96 subnet on the inside interface going to the outside
interface gets a static NAT66 translation to an address on the 2001:db8:122:2999::/96 network.
NAT66 Example, Simple IPv6 Int... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
244 | Rewriting DNS Queries and Responses Using NAT
You might need to configure the ASA to modify DNS replies by replacing the address in the reply with an
address that matches the NAT configuration. You can configure DNS modification when you configure each
translation rule. DNS modification is also known as DNS doctoring.
... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
245 | In this case, you want to enable DNSreply modification on thisstatic rule so that inside users who have access
to ftp.cisco.com using the real address receive the real address from the DNS server, and not the mapped
address.
When an inside host sends a DNS request for the address of ftp.cisco.com, the DNS server replie... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
246 | hostname(config-network-object)# nat (inside,outside) static 209.165.201.10 dns
DNS Reply Modification, DNS Server, Host, and Server on Separate Networks
The following figure shows a user on the inside network requesting the IP address for ftp.cisco.com, which
is on the DMZ network, from an outside DNS server. The DNS ... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
247 | Procedure
Step 1 Create a network object for the FTP server.
hostname(config)# object network FTP_SERVER
hostname(config-network-object)# host 209.165.201.10
Step 2 Configure static NAT with DNS modification.
hostname(config-network-object)# nat (outside,inside) static 10.1.2.56 dns
DNS64 Reply Modification
The followi... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
248 | the static translation. This example also includes a static NAT translation for the DNS server, and a PAT rule
for the inside IPv6 hosts.
Procedure
Step 1 Create a network object for the FTP server and configure static NAT with DNS modification. Because this
is a one-to-one translation, include the net-to-net option fo... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
249 | Example:
hostname(config)# object network IPv4_POOL
hostname(config-network-object)# range 209.165.200.230 209.165.200.235
Step 4 Create a network object for the inside IPv6 network, and configure dynamic NAT with a PAT pool.
hostname(config)# object network IPv6_INSIDE
hostname(config-network-object)# subnet 2001:DB8:... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
250 | P ART III
Service Policies and Application Inspection
• Service Policy, on page 231
• Getting Started with Application Layer Protocol Inspection, on page 253
• Inspection of Basic Internet Protocols, on page 273
• Inspection for Voice and Video Protocols, on page 311
• Inspection for Mobile Networks, on page 335 | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
251 | null | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
252 | CHAPTER 10
Service Policy
Service policies using Modular Policy Framework provide a consistent and flexible way to configure ASA
features. For example, you can use a service policy to create a timeout configuration that is specific to a
particular TCP application, as opposed to one that applies to all TCP applications.... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
253 | The class command defines the traffic matching criteria for the rule.
The commands associated with class, such as inspect, set connection timeout, and so forth, define the
services and constraints to apply to matching traffic. Note that inspect commands can point to inspection
policy maps, which define actions to apply... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
254 | class-map inside-class1
match access-list inside_mpc_2
: Policy map that actually defines the service policy rule set named test-inside-policy.
: In ASDM, this corresponds to the folder at call-out 1.
policy-map test-inside-policy
: First rule in test-inside-policy, named sip-class-inside. Inspects SIP traffic.
: The s... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
255 | See:
For Management
Traffic?
For Through
Feature Traffic?
TCP state bypass Yes No Connection Settings, on page 377.
See the user-statistics command in the command
reference.
User statistics for IdentityFirewall Yes Yes
Feature Directionality
Actions are applied to traffic bidirectionally or unidirectionally depending o... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
256 | Feature Matching Within a Service Policy
A packet matches class maps in a policy map for a given interface according to the following rules:
1. A packet can match only one class map in the policy map for each feature type.
2. When the packet matches a class map for a feature type, the ASA does not attempt to match it t... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
257 | 3. Application inspections that can be combined with other inspections:
a. IPv6
b. IP options
c. WAAS
4. Application inspections that cannot be combined with other inspections. See Incompatibility of Certain
Feature Actions, on page 236 for more information.
5. ASA FirePOWER (ASA SFR)
6. QoS output policing
7. QoS stan... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
258 | Example 1: Misconfiguration for FTP packets: HTTP Inspection Also Configured
class-map ftp
match port tcp eq 21
class-map http
match port tcp eq 21 [it should be 80]
policy-map test
class ftp
inspect ftp
class http
inspect http
Example 2: Misconfiguration for HTTP packets: FTP Inspection Also Configured
class-map ftp
m... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
259 | • ASA FirePOWER
• NetFlow Secure Event Logging filtering
• SCTP state bypass
• TCP and UDP connection limits and timeouts, TCP sequence number randomization
• TCP normalization
• TCP state bypass
• User statistics for Identity Firewall
Class Map (Traffic Class) Guidelines
The maximum number of class maps (traffic class... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
260 | • When you make service policy changes to the configuration, all new connections use the new service
policy. Existing connections continue to use the policy that was configured at the time of the connection
establishment. Output for the show command will not include data about the old connections.
For example, if you r... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
261 | class-map inspection_default
match default-inspection-traffic
policy-map type inspect dns preset_dns_map
parameters
message-length maximum client auto
message-length maximum 512
dns-guard
protocol-enforcement
nat-rewrite
policy-map global_policy
class inspection_default
inspect dns preset_dns_map
inspect ftp
inspect h3... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
262 | Configure Service Policies
To configure service policies using the Modular Policy Framework, perform the following steps:
Procedure
Step 1 Identify the traffic on which you want to act by creating Layer 3/4 class maps, as described in Identify Traffic
(Layer 3/4 Class Maps), on page 242.
For example, you might want to ... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
263 | See Configure Application Layer Protocol Inspection, on page 261.
Step 3 Define the actions you want to perform on each Layer 3/4 class map by creating a Layer 3/4 policy map, as
described in Define Actions (Layer 3/4 Policy Map), on page 246.
Step 4 Determine on which interfaces you want to apply the policy map, or ap... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
264 | Procedure
Step 1 Create a Layer 3/4 class map: class-map class_map_name
Where class_map_name is a string up to 40 characters in length.
The name “class-default” is reserved. All types of class maps use the same name space, so you cannot reuse
a name already used by another type of class map. The CLI enters class-map co... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
265 | the port number to determine the inspection applied, thus giving you the flexibility to apply inspections
to non-standard ports, for example.
See Default Inspections and NAT Limitations, on page 257 for a list of default ports. Not all applications
whose ports are included in the match default-inspection-traffic comman... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
266 | hostname(config-cmap)# description "This class-map matches all TCP traffic"
hostname(config-cmap)# match access-list tcp
hostname(config-cmap)# class-map all_http
hostname(config-cmap)# description "This class-map matches all HTTP traffic"
hostname(config-cmap)# match port tcp eq http
hostname(config-cmap)# class-map t... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
267 | Define Actions (Layer 3/4 Policy Map)
After you configure Layer 3/4 class maps to identify traffic, use a Layer 3/4 policy map to associate actions
to those classes.
Tip The maximum number of policy maps is 64, but you can only apply one policy map per interface.
Procedure
Step 1 Add the policy map: policy-map policy_m... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
268 | connection to http server.
hostname(config-pmap)# class http-server
hostname(config-pmap-c)# set connection conn-max 256
The following example shows how multi-match works in a policy map:
hostname(config)# class-map inspection_default
hostname(config-cmap)# match default-inspection-traffic
hostname(config)# class-map h... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
269 | You can only apply one global policy, so if you want to alter the global policy, you need to either edit
the default policy or disable it and apply a new one. By default, the configuration includes a global policy
that matches all default application inspection traffic and applies inspection to the traffic globally. Th... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
270 | Figure 45: HTTP Inspection and QoS Policing
See the following commands for this example:
hostname(config)# class-map http_traffic
hostname(config-cmap)# match port tcp eq 80
hostname(config)# policy-map http_traffic_policy
hostname(config-pmap)# class http_traffic
hostname(config-pmap-c)# inspect http
hostname(config-p... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
271 | Applying Inspection and Connection Limits to HTTP Traffic to Specific Servers
In this example, any HTTP connection destined for Server A (TCP traffic on port 80) that enters the ASA
through the outside interface is classified for HTTP inspection and maximum connection limits. Connections
initiated from Server A to Host... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
272 | Applying Inspection to HTTP Traffic with NAT
In this example, the Host on the inside network has two addresses: one is the real IP address 192.168.1.1, and
the other is a mapped IP address used on the outside network, 209.165.200.225. You must use the real IP
address in the ACL in the class map. If you applied it to th... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
273 | Feature Name Releases Description
Regular expressions and policy maps were
introduced to be used under inspection
policy maps. The following commands
were introduced: class-map type regex,
regex, match regex.
Regular expressions and policy maps 7.2(1)
The match any keyword was introduced
for use with inspection policy ... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
274 | CHAPTER 11
Getting Started with Application Layer Protocol
Inspection
The following topics describe how to configure application layer protocol inspection.
• Application Layer Protocol Inspection, on page 253
• Configure Application Layer Protocol Inspection, on page 261
• Configure Regular Expressions, on page 268
• M... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
275 | When you enable application inspection for a service that uses dynamically assigned ports, the ASA monitors
sessions to identify the dynamic port assignments, and permits data exchange on these ports for the duration
of the specific session.
Inspection Policy Maps
You can configure special actions for many application ... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
276 | match request header host length gt 100
reset
match request method get
log
If an action drops a packet, then no further actions are performed in the inspection policy map. For example,
if the first action isto reset the connection, then it will never match any further match criteria. If the first action
is to log the p... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
277 | Clustering
The following inspections are not supported in clustering:
• CTIQBE
• H323, H225, and RAS
• IPsec passthrough
• MGCP
• MMP
• RTSP
• SCCP (Skinny)
• WAAS
IPv6
Supports IPv6 for the following inspections:
• Diameter
• DNS over UDP
• FTP
• GTP
• HTTP
• ICMP
• IPsec pass-through
• IPv6
• M3UA
• SCCP (Skinny)
• S... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
278 | • SCTP
Additional Guidelines
• Some inspection engines do not support PAT, NAT, outside NAT, or NAT between same security
interfaces. For more information about NAT support, see Default Inspections and NAT Limitations, on
page 257.
• For all the application inspections, the ASA limits the number of simultaneous, active... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
279 | Table 12: Supported Application Inspection Engines
NAT Limitations Standards Comments
Default Protocol,
Application Port
No extended PAT. — —
No NAT64.
(Clustering) No static PAT.
CTIQBE TCP/2748
DCERPC TCP/135 No NAT64. — —
TCP/3868 No NAT/PAT. RFC 6733 Requires the Carrier license.
TCP/5868 (for
TCP/TLS)
SCTP/3868
Di... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
280 | NAT Limitations Standards Comments
Default Protocol,
Application Port
RFC 791, RFC —
2113
IP Options RSVP No NAT64.
No PAT. — —
No NAT64.
IPsec Pass UDP/500
Through
IPv6 — No NAT64. RFC 2460 —
LISP — No NAT or PAT. — —
No NAT or PAT for embedded RFC 4666 Requires the Carrier license.
addresses.
M3UA SCTP/2905
No extend... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
281 | NAT Limitations Standards Comments
Default Protocol,
Application Port
Does not handle TFTP uploaded
Cisco IPPhone configurations under
certain circumstances.
No NAT/PAT on interfaces with the RFC 2543
same, or lower to higher, security
levels.
No extended PAT.
No NAT64 or NAT46.
(Clustering) No static PAT.
TCP/5060
UDP... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
282 | class-map inspection_default
match default-inspection-traffic
policy-map type inspect dns preset_dns_map
parameters
message-length maximum client auto
message-length maximum 512
dns-guard
protocol-enforcement
nat-rewrite
policy-map global_policy
class inspection_default
inspect dns preset_dns_map
inspect ftp
inspect h3... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
283 | Procedure
Step 1 Unless you are adding inspection to an existing class map, create an L3/L4 class map to identify the traffic
for which you want to apply the inspection.
class-map name
match parameter
Example:
hostname(config)# class-map dns_class_map
hostname(config-cmap)# match access-list dns
In the default global p... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
284 | Table 13: Inspection Protocol Keywords
Keywords Notes
ctiqbe See CTIQBE Inspection, on page 311.
See DCERPC Inspection, on page 273.
If you added a DCERPC inspection policy map according to Configure
a DCERPC InspectionPolicy Map, on page 274, identify the map name
in this command.
dcerpc [map_name]
See Diameter Inspec... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
285 | Keywords Notes
See H.323 Inspection, on page 312.
If you added an H323 inspection policy map according to Configure
H.323 Inspection Policy Map, on page 314, identify the map name in
this command.
h323 h225 [map_name]
See H.323 Inspection, on page 312.
If you added an H323 inspection policy map according to Configure
H... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
286 | Keywords Notes
See M3UA Inspection, on page 338.
If you added an M3UA inspection policy map according to Configure
an M3UA Inspection Policy Map, on page 360, identify the map name
in this command.
m3ua [map_name]
See MGCP Inspection, on page 317.
If you added an MGCP inspection policy map according to Configure
an MGC... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
287 | Keywords Notes
See Skinny (SCCP) Inspection, on page 328.
If you added a Skinny inspection policy map according to Configure a
Skinny (SCCP) Inspection Policy Map, on page 330, identify the map
name in this command.
tls-proxy proxy_name identifiesthe TLSproxy to use for thisinspection.
You need a TLSproxy only if you w... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
288 | The global keyword applies the policy map to all interfaces, and interface applies the policy to one interface.
Only one global policy is allowed. You can override the global policy on an interface by applying a service
policy to that interface. You can only apply one policy map to each interface.
Choosing the Right Tr... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
289 | Configure Regular Expressions
Regular expressions define pattern matching for text strings. You can use these expressions in some protocol
inspection maps to match packets based on strings such as URLs or the contents of particular header fields.
Create a Regular Expression
A regular expression matches text strings eit... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
290 | Character Description Notes
A quantifier that indicates that there are 0, 1 or any
number of the previous expression.For example,lo*se
matches lse, lose, loose, and so on.
* Asterisk
A quantifier that indicates that there is at least 1 of
the previous expression. For example, lo+se matches
lose and loose, but not lse.
... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
291 | Character Description Notes
Matches an ASCII character as octal (exactly three
digits). For example, the character 040 represents a
space.
\NNN Escaped octal number
Procedure
Step 1 Test a regular expression to make sure it matches what you think it will match: test regex input_text
regular_expression
Where the input_t... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
292 | Where class_map_name is a string up to 40 characters in length. The name “class-default” is reserved. All
types of class maps use the same name space, so you cannot reuse a name already used by another type of
class map.
The match-any keyword specifies that the traffic matches the class map if it matches at least one o... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
293 | • show ctiqbe
Displays information about the media connections allocated by the CTIQBE inspection engine
• show h225
Displays information for H.225 sessions.
• show h245
Displays information for H.245 sessions established by endpoints using slow start.
• show h323 ras
Displays connection information for H.323 RAS sessi... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
294 | CHAPTER 12
Inspection of Basic Internet Protocols
The following topics explain application inspection for basic Internet protocols. For information on why you
need to use inspection for certain protocols, and the overall methods for applying inspection, see Getting
Started with Application Layer Protocol Inspection, on... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
295 | DCERPC Overview
Microsoft Remote Procedure Call (MSRPC), based on DCERPC, is a protocol widely used by Microsoft
distributed client and server applications that allows software clients to execute programs on a server remotely.
This typically involves a client querying a server called the Endpoint Mapper listening on a ... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
296 | Where class_map_name isthe name of the class map. The match-all keyword isthe default, and specifies
that traffic must match all criteria to match the class map. The match-any keyword specifiesthat the traffic
matches the class map if it matches at least one match statement. The CLI enters class-map configuration
mode.... | https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config.pdf |
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