Re: [SR-Users] Using path with DMQ to send calls to origin SBC - not sure when to modify destination URI

On Nov 29, 2021, at 8:25 AM, Rhys Hanrahan &lt;rhys(a)nexusone.com.au&gt; wrote: Thanks Alex! I am already doing steps 1, 2, 3 and 5, but I am using the received parameter though, with "path_use_received". I am wondering what your reasoning is to not use the received parameter? With it involved, things (including NAT traversal) seem to mostly "just work", provided I set the destination URI on the home registrar. Interested to know your reasoning, though? Will have to work through your example and see how I go as it's a fair bit different to what I have now and I'm still learning! Thanks for the tip on "dmq_is_from_node" - I was looking for a more elegant way of allowing traffic from other SBCs without a bunch of IP whitelists, and this looks like the way to go! Thanks for your help. Rhys. On 29/11/21, 11:44 pm, "Alex Balashov" &lt;abalashov(a)evaristesys.com&gt; wrote: Hi, I had started the first of the original threads you referenced, so thought I might chime in here. :-) The best practices here (in the eye of this beholder): 1) Enable `path_check_local` in the registrar module: https://kamailio.org/docs/modules/stable/modules/registrar.html#registrar.p… This will allow you to have the same logic on every node without explicit attention in route config script to whether the home registrar of the registering endpoint == myself. 2) Enable `use_path` in the registrar module in the first place: https://kamailio.org/docs/modules/stable/modules/registrar.html#registrar.p… This will allow `lookup()` to set the destination URI ($du) transparently to you. 3) Set `path_mode` to 0 in registrar: https://kamailio.org/docs/modules/stable/modules/registrar.html#registrar.p… 4) Dispense with `received` altogether and use only `{set,add}_contact_alias()` and `handle_ruri_alias()` for server-side NAT traversal. This concern was essentially spurious on my part. 5) Prior to `save()`ing a registration, add your own Path header with the local hop address: append_hf(“Path: <sip:$Ri:5060;lr>\r\n”); msg_apply_changes(); # I forget if this is needed here. if(!save(“location”)) { … } 6) You need to add logic on the endpoint’s “home registrar” to pass through requests bound for a local registrant but resolved on a different ingress registrant, but still deal with NAT and such. I do this in the main request route using something like the below: route { … t_check_trans(); … # Initial request handling of various kinds. if(uri == myself) { … } else { # Any initial requests not addressed to a local domain # are rejected unless they are laterally routed from a DMQ # peer. if(dmq_is_from_node()) { if(is_method(“INVITE”)) record_route(); # Add ourselves to signalling chain. handle_ruri_alias(); t_on_reply(“NAT_AND_SUCH_REPLY”); if(!t_relay()) sl_reply_error(); } else { sl_send_reply(“403”, “Forbidden”); } } } 7) Handle any RTP anchoring on the ingress proxy (the one the call came in on) as opposed to the last-hop/home registrar. Hope that helps! — Alex -- Alex Balashov | Principal | Evariste Systems LLC Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) Web: http://www.evaristesys.com/, http://www.csrpswitch.com/ __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions * sr-users(a)lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender! Edit mailing list options or unsubscribe: * https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions * sr-users(a)lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender! Edit mailing list options or unsubscribe: * https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users