SRTP problems

Asterisk Asterisk Support
1

Hi

I’m trying to setup a Tiptel 3230 to make encrypted calls and connections.

This is what I have in sip.conf:

type=friend
defaultuser=homeworker.01
callerid="Homeworker Dude"
host=dynamic
secret=IeEujJEdudTdZmkL
context=homeworkers
dtmfmode=rfc2833
callgroup=15
pickupgroup=12,15
transport=tls
encryption=yes

In the account settings on the phone, I setup TLS over port 5061. This works fine, as far as I can tell. So, the SIP-signalling is secure. But as soon as I set SRTP as compulsory, things go haywire.

I can see the phone connecting in the Asterisk CLI. As soon as the phone is reachable, I can make 1 call. Either from that phone, or to that phone. As soon as I hangup, I see lots of these messages in the CLI:

[Mar 17 11:56:19] WARNING[2683]: chan_sip.c:3906 __sip_xmit: sip_xmit of 0x7fc09c001b70 (len 641) to 123.123.123.123:2486 returned -2: Interrupted system call

This keeps going for a while. And all this time I can’t call to that phone. If I do, I get the message that the phone is unreachable. If I try to call with that phone, I get nothing. Not a busy tone, not a dial tone. Just nothing.

It’s almost like the phone is still calling, or something. But if I do core show channels, Asterisk says there are 0 active calls and 0 active channels.

This keeps going on for several minutes, until I see this in the CLI

[Mar 17 11:56:33] WARNING[2683]: chan_sip.c:3906 __sip_xmit: sip_xmit of 0x7fc09c001b70 (len 641) to 123.123.123.123:2486 returned -2: No such file or directory
[Mar 17 11:56:35] NOTICE[10837]: chan_sip.c:23522 handle_response_peerpoke: Peer 'homeworker.01' is now Reachable. (39ms / 2000ms)

This time I could actually make several calls from and to the encrypted phone. It even shows a lock in the display, to indicate the call is encrypted. But after a few calls, I see this in the CLI

[Mar 17 12:24:37] WARNING[2683]: chan_sip.c:3906 __sip_xmit: sip_xmit of 0x7fc09c001b70 (len 641) to 123.123.123.123:1235 returned -2: Interrupted system call
[Mar 17 12:24:41] NOTICE[2683]: chan_sip.c:29427 sip_poke_noanswer: Peer 'homeworker.01' is now UNREACHABLE!  Last qualify: 51
[Mar 17 12:24:51] WARNING[2683]: chan_sip.c:3906 __sip_xmit: sip_xmit of 0x7fc09c001b70 (len 641) to 123.123.123.123:1235 returned -2: Interrupted system call

And the phone is unreachable for a few minutes again.

This is driving me nuts! I can’t figure out why it doesn’t work.

Any suggestions?

Thanks in advance! :smiley: