[Jemson]

Hi all,

Have encountered a strange issue that perhaps you may be able to help me with.

Basically what I have setup, in an Asterisk box in my office that registers SIP accounts with an upstream provider, and office users also register with the server for internal and external communications. (Although there is only 1 interface in the machine on a Real-World IP)

The issue seems to be, when the upstream provider is down or un-contactable the Asterisk server, while trying to re-register with the ITSP "freezes". Basically when in the Asterisk console, you can see the re-tries at remote registration, but while this is happening, you cannot issue a reload, or any other command for that matter. It just defaults to the next line of the console.

In addition to this, office phones become unable to call one another, as they timeout trying to contact the asterisk server.

This is a pain, as I wish to be able to use office-office communications in the event the ITSP is down.

Any Ideas? I am very keen to rectify this asap.

- Jemson

[funman1]

To my understanding, which is limited. If the phones can not contact a server, they have no clue who else is on the network to contact. The server is like main hub for ALL communications.

Like if the phone company went down, you could not call your neighbor next door. Even though you are both on the same switch at the end of the street. If it can't authenticate it won't work.

This is not gospel, and if I'm off I hope someone will correct me, but this is my understanding of how it works.

~Steve~

[Jemson]

I dont see how that can be correct, as if the registration line is commented out, internal communications are fine.

In addition to this, the CONSOLE SESSION locks up also. This should be COMPLETELY independent of any registration issues.

[chandave]

Asterisk will appear to hang if it cannot retrieve DNS information. It might just be that your Asterisk server is stuck waiting for a DNS SRV (Service) record or a DNS A (address) record.

The next time it hangs, try and see if you can resolve any IP addresses (i.e. at the command line issue:

nslookup -q=srv _sip._udp.incoming.vtnoc.net (MS-Windows)
dig _sip._udp.incoming.vtnoc.net srv (Linux/Unix)

If it times out, then the problem is the DNS server you are using. In that case, you might want to run a caching DNS server on your Asterisk box.

See ya...

d.c.

[Cybertoy]

I suspect the last poster is spot-on ... I had a similar problem a while ago. Make sure you never use any host-names in your asterisk configuration but only IP addresses unless you run your own DNS server. I decided to run my own DNS server as I think it's bad practice to hardcode IP addresses. However you depend on your DNS service.