Re: [SR-Users] Having kamailio bind to a VRF device

On 11 Oct 2017, at 22:07, George Diamantopoulos &lt;georgediam(a)gmail.com <mailto:georgediam@gmail.com>> wrote: Hello Daniel, I'm including the original sketch for clarity: +----------+ +-------------------+ | eth0 | | vrf-green | | 1.1.1.1 | | 127.0.0.1 | +----------+ +-------------------+ | +----------+ | eth1 | | 2.2.2.2 | +----------+ Thanks for the reply. Indeed, using the advertise option for the "listen" directive will result in kamaiio no longer failing to start when using force_send_socket(2.2.2.2:5060 <http://2.2.2.2:5060/>) with 2.2.2.2 being used in the "advertise" option. However, this doesn't make much of a difference in that kamailio still won't process IP packets arriving on eth1 at IP 2.2.2.2... I can see OPTIONS coming with sngrep, but nothing in the logs, no replies, only retransmissions from the originator. In addition, while without VRF kamailio will select the right interface with mhomed=1, this is no longer the case. Also, If I try to send something to a host with force_send_socket, the transaction fails with 477 Unfortunately error on sending to next hop occurred. In the log, kamailio prints something along the lines of: udp_send(): sendto(sock,0x7f5c4f937d08,1888,0,9.9.9.9:5060 <http://9.9.9.9:5060/>,16): Invalid argument(22) udp_send(): invalid sendtoparameters msg_send_buffer(): udp_send failed where 9.9.9.9 is the $dd and presumably force_send_socket(2.2.2.2:5060 <http://2.2.2.2:5060/>) has been called before t_relay() Also, I additionally found out that if the networking configuration is as follows: +----------+ +-------------------+ +-------------------+ | eth0 | | vrf-green | | vrf-red | | 1.1.1.1 | | 127.0.0.1 | | 127.0.0.1 | +----------+ +-------------------+ +-------------------+ | | +----------+ +----------+ | eth1 | | eth2 | | 2.2.2.2 | | 3.3.3.3 | +----------+ +----------+ Then this won't work for vrf-red: listen=vrf-green:5060 advertise 2.2.2.2:5060 <http://2.2.2.2:5060/> listen=vrf-red:5060 advertise 3.3.3.3:5060 <http://3.3.3.3:5060/> One needs to use different IPs for the MASTER devices (say 127.0.0.1 and 127.0.0.2) for kamailio to startup with the above listen directives. It's a bit surprising it doesn't work. According to a user on cumulus slack channel (cumulus contributed the VRF code to the linux kernel): "any app that has a command line or option switch to call SO_BINDTODEVICE on the sockets can be configured to use any VRF". I guess the problem lies in that kamailio binds to several sockets and there are multiple routing tables to consult, so mhomed doesn't work as expected (if every table has a default route and nothing more specific than that). But still, this doesn't really explain why binding to the VRF master net devices doesn't work (I mean, "ping -I vrf-green" works just fine for ping)... I don't think VRF support is very useful for most users though, I just had one corner case I needed to tackle and VRF seemed like an easy fix. I'll think of an alternative at some point, I guess. On 26 September 2017 at 09:52, Daniel-Constantin Mierla &lt;miconda(a)gmail.com <mailto:miconda@gmail.com>> wrote: _______________________________________________ Kamailio (SER) - Users Mailing List sr-users(a)lists.kamailio.org <mailto:sr-users@lists.kamailio.org> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users <https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users>