[asterisk-users] Internet gateway problem

[Robert Lister]

On Mon, Apr 23, 2007 at 11:12:15AM +0200, voip crazy wrote:
> Hello all,
> 
> I have got an asterisk server in my LAN, getting access to internet trought
> a router. I have observed in my asterisk box, when the internet connection
> in down, the phones can not register to my asterisk. It is like chan_sip,
> does not work without an internet connection.
> If when the router is down the telephones does not register, but when I type
> in my asterisk box "route del default", teh phones then started to register
> against the asterisk.

Is there any debugging information available from the logs/console?

Does your server have a fixed IP address or does it change about?

> Why this is happenning?
> Why chan_sip, need a gateway or it does not start correctly?
> Why when I type "route del default" the phones started to register?

I have seen similar issues recently with asterisk SIP service when DNS 
becomes unavailable, the chan_sip dies because the DNS lookups are blocking, 
and it has to wait for every request to time out.

If your box has no default route, then it will respond immediately with 
a Network Unreachable message rather than wait for the DNS to time out.

If you have any outbound "register =>" entries try taking them out and 
experimenting with the line down. Also if you have any hints in 
extensions.conf try taking those out.

Asterisk seems to make many spurious DNS requests.
http://bugs.digium.com/view.php?id=9536

A possible workaround which I have implemented here, is to have a local 
instance of BIND on the asterisk box which slaves for the local zones and 
caches things, so that it does not die so often.

Rob


-- 
Robert Lister   -   London Internet Exchange    -  http://www.linx.net/
robl at linx.net   -   tel: +44 (0)20 7645 3510    -  RL786-RIPE