[Asterisk-Users] RE: Problem with multiple phones behind firewall

[Harold Workman]

Sorry for the second email, but be a little more clear.  I am making the
test call to Phone A and Phone B from PSTN Cisco Gateway.  Calls are routed
to * via SIP from Cisco 7206


PSTN ---> Cisco ---> * ---> IP Phone



Harold Workman wrote:
> Hi,
>
> I am having a problem when I add multiple phones behind a Symmetric
> Firewall.  Heres my situation.
>
>
> 11am - Phone A registers with *
> 11:01am - test call to Phone A.  Call works fine.
> 11:02am - Phone B registers with *
> 11:03am - test call to Phone A fails, test call to phone B works fine.
> 11:04am - test call from Phone A to Phone B and vice versa works fine.
> 11:05am - Phone A re-registers with *.  Test call to Phone A works
> fine now.
>
>
>
> This happens on almost all occasions.  When I see one phone register
> behind a firewall, i then see the "Retransmitting #5 (NAT):"
> messages, until I received the "Jul 13 15:11:09 WARNING[1133718080]:
> chan_sip.c:673 retrans_pkt: Maximum retries exceeded on call
> 0576f80274aebde8796e5d4b2444c2a9 at 64.72.107.10 for seqno 102
> (Non-critical Request)"
>
>
> I have nat=yes in my sip.conf file.  I have tried using the qualify
> command, but I have never been able to get it to work behind a
> symmetric firewall to both a unknown sip phone and xlite. The moment
> I turn on qualify, I see the Options request sent out, and on the
> client see the options request, but I never see a response on * from
> the clients.
>
>
>
> Here is what my sip.conf looks like...
>
>
> [general]
> port = 5060
> bindaddr = 64.72.107.10
> context = exten
> maxexpirey=3000
> defaultexpirey=300
> disallow=all
> allow=alaw
> allow=ulaw
>
> [123456]
> type=friend
> secret=k3v1n
> nat=yes
> canreinvite=no
> host=dynamic
> dtmfmode=rfc2833
> context=cytelmain
>
> [789012]
> type=friend
> secret=cytel
> nat=yes
> canreinvite=no
> host=dynamic
> dtmfmode=rfc2833
> context=cytelmain
>
>
>
> What else is there for me to try to resolve my NAT problem with
> multiple users behind a symmetric firewall?
>
>
> Thanks,
>
>
>
> Harold