text stringlengths 0 152 |
|---|
Chapter 4: Certificates for Endpoint Security |
If you’ve got a web server running, or are confident with option 2, that is OK, but |
these steps assume you don’t have a web server running, and thus will need/want to |
use the built-in temporary web server that certbot will use to authenticate. This |
server is used to prove that you control the domain you’re requesting a certificate for. |
Answer the next questions as appropriate, and then at this point you will insert the |
hostname that you assigned to the IP address of your server: |
Please enter in your domain name(s) (comma and/or space separated) (Enter 'c' |
to cancel): asteriskbook.shifteight.org |
(replace asteriskbook.shifteight.org with the domain name you assigned). |
certbot will perform its magic, and if all went well you should get some sort of mes‐ |
sage similar to the following: |
IMPORTANT NOTES: |
- Congratulations! Your certificate and chain have been saved at: |
/etc/letsencrypt/live/asteriskbook.shifteight.org/fullchain.pem |
Your key file has been saved at: |
/etc/letsencrypt/live/asteriskbook.shifteight.org/privkey.pem |
Your cert will expire on 2018-07-23. To obtain a new or tweaked |
version of this certificate in the future, simply run certbot |
again. To non-interactively renew *all* of your certificates, run |
"certbot renew" |
- Your account credentials have been saved in your Certbot |
configuration directory at /etc/letsencrypt. You should make a |
secure backup of this folder now. This configuration directory will |
also contain certificates and private keys obtained by Certbot so |
making regular backups of this folder is ideal. |
- If you like Certbot, please consider supporting our work by: |
Donating to ISRG / Let's Encrypt: https://letsencrypt.org/donate |
Donating to EFF: https://eff.org/donate-le |
Don’t forget to donate to the Internet Security Research Group (ISRG) or the Elec‐ |
tronic Frontier Foundation (EFF); they do important work and deserve our support. |
You now have the certificates you’ll need for enabling various TLS services on your |
system. We’ll put them to use in the next chapter. |
Not too difficult, eh? |
Bear in mind that most certificates you get from an outside source |
will have an expiration date. In the case of LetsEncrypt, the current |
validity is three months. If you are going to put certificates into |
production, it is up to you to understand how to manage them (for |
example, automating renewal, which the LetsEncrypt folks have |
done a good job of simplifying). |
Securing SIP |
| |
53 |
Purchasing certificates from a formal certificate authority |
If LetsEncrypt certificates do not provide the level of validation you require—for |
example, if you need organization validation (OV) or extended validation (EV)—you |
will need to obtain the services of a certificate authority that provides such things. |
These matters are beyond the scope of this book. |
If you have worked through the examples for the self-signed and LetsEncrypt sec‐ |
tions, you’ll have at least a basic understanding of some of the process of obtaining |
certificates from a certificate authority, as many of the steps will be similar. |
Securing Media |
The certificates we’ve obtained can be used to secure both our signaling, and the pay‐ |
load itself (i.e., what’s being spoken, or the video being transmitted). Note that the |
mechanisms to secure signaling are an SIP protocol thing, and the mechanisms to |
secure the media are an RTP protocol thing. Keep in mind that encrypting your SIP |
signaling does not mean you’re automatically also encrypting your media (RTP) |
traffic. |
Encrypted RTP |
Encrypting the Real Time Protocol will achieve the effect of securing our media |
streams. |
There are two mechanisms commonly used to provide media encryption: SDES and |
DTLS-SRTP. SDES is a media encryption mechanism that trusts that the signaling is |
secure. In other words, if you are using TLS to secure your SIP signaling, then SDES |
is likely how your media encryption is being handled. |
DTLS-SRTP, on the other hand, does not trust the signaling. It is important because |
the WebRTC standard requires that media be encrypted this way. |
The certificates we’ve generated here should work in both scenarios. In upcoming |
chapters, when we are configuring SIP or WebRTC endpoints, we will cover in more |
detail how to use the certificates. For now, it’s enough that we’ve generated the certifi‐ |
cates and have them available for use. |
Conclusion |
Make no mistake: security makes everything more complicated. In the good old days, |
you could fire up a SIP connection with a half-dozen lines of config and call it a day. |
That doesn’t fly anymore, and while that type of configuration will still work (simply |
use UDP instead of TLS, and all you need is a password), we decided that starting |
with this edition, all configuration examples will choose more secure options |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.