Re: [Serusers] use_dns_cache and call forwarding

On 07/24/2008 01:11 PM, caio wrote:

Hi Miklos, This happens only when I try to do a call to a subcriber having forwarding enabled.

Normal calls success ok. I'm not sure about the append_branch() usage and how to work with 'on busy' and 'no answer' forwarding features.

The config script looks fine, I suppose you see the log messages "LOG: --> appending new branch..." and "LOG: --> Calling route_6..." before the error logs you posted.

SER tries to forward the call to wsa.lab. It tries to resolve the SRV record first without success, than resolves the A record (there is no error, so the resolution is ok).

I believe there is a routing or firewall problem, because sendto() function returns with error, so the issue is not SER-related in my opinion, try to google for "sendto operation not permitted". Disable iptables or any other firewall you have, verify that the routing is correct, and SER listens on the interface that is used to send out the packet.

I would also try to send a call to wsa.lab without failure route with a very simple ser script.

Miklos

Thanks your comments..

Claudio

On Thu, Jul 24, 2008 at 4:58 AM, Miklos Tirpak miklos@iptel.org wrote:

...

Hi,

On 07/23/2008 05:22 PM, caio wrote:

...

Hi guys, I have a problem with call forwarding (on busy or not answer).., the call fall into the failure_route(1) block, and AVP checking and pushto does its job.

Here a snipped of code of failure_route(1) (flag 27 means call fwd if no answer):

   if (isflagset(27) && t_check_status("408")) { # if fwd no

answer is set and reply msg is 408

           if (avp_pushto("$ruri", "s:fwdnoanswer")) {
                   avp_delete("s:fwdnoanswer");
                   resetflag(27);

                   avp_print();

                   log(1, "LOG: --> appending new branch...");
                   if (!append_branch()){
                           t_reply("500", "Too many branches?!");
                           drop;
                   }

                   log(1, "LOG: --> Calling route_6...");
                   route(6);
                   break;

Route(6) finally calls route(1), where t_relay is called. But have a dns failure..and the call never is forwarded.

== ser.log ==

DEBUG: mk_proxy: doing DNS lookup... get_record: lookup(_sip._udp.wsa.lab, 33) failed_ sip_resolvehost: no SRV record found for wsa.lab, trying 'normal' lookup..._ check_via_address(190.244.33.5, 190.244.33.5, 0)_ ERROR: udp_send: sendto(sock,0x2ab32599c720,910,0,0x2ab325999e68,16): Operation not permitted(1)_ msg_send: ERROR: udp_send failed_ ERROR: t_forward_nonack: sending request failed_ DEBUG: add_to_tail_of_timer[4]: 0x2ab325999e80_ DEBUG: add_to_tail_of_timer[0]: 0x2ab325999ea0_ ERROR: w_t_relay (failure mode): forwarding failed_

A question regarding this trouble.....Can I disable use_dns_cache ? SER version is 0.9.7.

there is no DNS cache in version 0.9.x as I recall, but anyway, your problem does not seem to be related to DNS, but to the UDP message sending: SER fails to send out the UDP packet, "Operation not permitted". Is there no firewall or routing problem at the proxy side?

Miklos

...

What do you recommend? If you need my ser.cfg I can paste it...

Thanks..

-- caio