Oh and one more thing regarding the default of no media encryption by default:

> Il giorno Nov 10, 2014, alle ore 12:54 AM, Ben Klang <[email protected]> 
> ha scritto:
> 
> Tonight I finally got Asterisk 13 working with chan_pjsip and SIP+TLS and 
> RTP+DTLS.  It’s 12:45am so I won’t spend a lot of time on this now, but I 
> wanted to share the notes I took while setting this up as I feel the 
> documentation is pretty lacking in this area.
> 
> 
> media_encryption is not well documented in pjsip.conf
> * In my case, it needed to be set to “dtls”, but I think that some endpoints 
> may need “srtp"
> * my first-guess setting of “yes” results in a cryptic/unhelpful error on the 
> console, and the syntax error caused the entire endpoint to be un-useable
> * dtls vs.srtp is not mentioned at all (as far asI could find) in either the 
> Asterisk Wiki nor the configs/sample/pjsip.conf
> * The default is “no” - I had thought that SRTP and DTLS were not mutually 
> exclusive - are they? If not, can we set a default that permits them to be 
> used if requested by the endpoint?

The default of “no” causes a “488 Not Acceptable Here” response, but nothing in 
the pjsip (pjsip set log on) or Asterisk debug logs (core set debug 5) says why 
it was refused. I went down a road of disabling codecs to no avail.  A note 
that encryption was requested but not configured would have helped.

> 
> Configuring certificates
> There is no mention of the fact that endpoints need DTLS certificates 
> configured at all on endpoints in the Asterisk Wiki.
> The Asterisk Wiki covers setting up TLS on the transport, and that mostly 
> worked on the first go *except* that the config key is erroneously referenced 
> as “privkey_file” (missing an underscore).  I made a comment on the Wiki so 
> someone can correct this, but it appears to have been included in sample 
> config files for some time, so the bad info is out there: 
> https://duckduckgo.com/?q=asterisk+%22privkey_file%22 
> <https://duckduckgo.com/?q=asterisk+%22privkey_file%22>
> Also, it might be worth mentioning that TLS runs over TCP, not UDP, as I had 
> that wrong in my firewall on the first attempt.
> 
> Setting certificates has to be done at least twice (transport + endpoint)
> * There is no automatic setting of the DTLS CA/Cert/Privkey from the SIP+TLS 
> configuration for the transport. I know this would potentially be difficult 
> if multiple transports were set with different TLS keys, but still…this is 
> non-obvious.
> * Can we somehow default the endpoint’s CA/Cert/Privkey to that of the 
> transport? If not, can we somehow associate the endpoint with the transport 
> so it doesn’t have to be configured twice?
> 
> The pjsip configuration keys are subtly different for SIP+TLS on the 
> transport vs. RTP+DTLS on the endpoint. Examples:
> 
> cert_file =X ; transport
> dtls_cert_file = X ; endpoint
> ; dtls_ prefix, weird but ok - srtp doesn’t appear to have a corresponding 
> setting, so do we even need the prefix?
> 
> priv_key_file = X ; transport
> dtls_private_key = X ; endpoint
> ; priv_key_file vs. private_key?
> 
> ca_list_file =X ; transport
> dtls_ca_file = X ; endpoint
> ; _list or not?
> 
> I’m not familiar with Sorcery.  I know that Asterisk 13 is out meaning these 
> config settings are set in stone for the next couple of years. But could we 
> create aliases that were more consistent, just to preserve some peoples’ hair?
> 
> But the good news is: it does work! :)
> 
> /BAK/
> --
> Ben Klang
> Principal/Technology Strategist, Mojo Lingo
> [email protected] <mailto:[email protected]>
> +1.404.475.4841
> 
> Mojo Lingo -- Voice applications that work like magic
> http://mojolingo.com <http://mojolingo.com/>
> Twitter: @MojoLingo
> 
> --
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