| #### PassiveDNS internals |
|
|
| ## Packet capture |
| * Uses libpcap |
| * Decodes packets as they come in. |
| * Handles vlan (looks inside vlan packets, but does not |
| currently print out the vlan tag seen) |
| * Handles IPv4 and IPv6 packets |
| * We look at DNS on UDP and TCP |
|
|
| ## Connection Tracking |
| * Same connection tracking as in cxtracker |
| ** When used with a propper BPF (filter), |
| it only tracks traffic on port 53. |
| * Connection tracking is used to make sure |
| that a client asked for a domain, so that |
| there will not be any tracking of domains, |
| if a client did not request one. A bit spoof |
| protection. In the connection data, the |
| DNS Transaction ID is also stored, to verify |
| that the client sent a request, and that the |
| server answered the right TID request :) |
|
|
| ## Domain caching |
| * When a DNS question and answer is recieved, it |
| is stored in an internal linked list. If its new, |
| we will print the info to the logfile, and we will |
| not print it again befor it has gone 12 hours or |
| the record has changed. This is to provent flooding |
| of data to the log file, and serving you much duplicat |
| info. |
| * If we have not seen any activity agains a domain in 24h, |
| it will be deleted from the internal cache. |
| * If we have not seen any activity of any related entries |
| within 24h, it will be deleted... |
|
|
|
|
|
|
