Messages in this thread |  | | Date | Fri, 18 Jan 2013 00:35:39 +0100 | From | Pablo Neira Ayuso <> | Subject | Re: [PATCH v4] netfilter: nf_conntrack_sip: Handle Cisco 7941/7945 IP phones |
| |
On Mon, Dec 17, 2012 at 08:33:58PM -0800, Kevin Cernekee wrote: > Most SIP devices use a source port of 5060/udp on SIP requests, so the > response automatically comes back to port 5060: > > phone_ip:5060 -> proxy_ip:5060 REGISTER > proxy_ip:5060 -> phone_ip:5060 100 Trying > > The newer Cisco IP phones, however, use a randomly chosen high source > port for the SIP request but expect the response on port 5060: > > phone_ip:49173 -> proxy_ip:5060 REGISTER > proxy_ip:5060 -> phone_ip:5060 100 Trying > > Standard Linux NAT, with or without nf_nat_sip, will send the reply back > to port 49173, not 5060: > > phone_ip:49173 -> proxy_ip:5060 REGISTER > proxy_ip:5060 -> phone_ip:49173 100 Trying > > But the phone is not listening on 49173, so it will never see the reply. > > This patch modifies nf_*_sip to work around this quirk by extracting > the SIP response port from the Via: header, iff the source IP in the > packet header matches the source IP in the SIP request.
Applied, thanks Kevin.
|  |