Hi Matt, When a non-NATed incoming call to a NATed client is processed (INVITE), you must make sure that you have a t_on_reply("1"); before you call t_relay (or forward). The INVITE will not be detected as behind a NAT, but the destination is (flag is set), and the reply will take care of the rewrite. In your config, it looks like you call t_relay before setting t_on_reply("1"); further down. A forward will only forward the SIP INVITE to another SIP proxy for processing. Paul (Java Rockx) just recently posted his config file with a working NAThelper/RTPproxy setup. I suggest you look at the call logic found there. His config is also easy to read with a lot of nice headers I haven't tested RTP proxy between a client behind NAT and Asterisk, but I believe that as long as you record-route the INVITE (as you do) and handle the replies properly, it should work. g-)
Matt Schulte wrote:
Another note to this, I moved my 'forward' and lookup statements down below the t_onreply statement. I figured this should allow ser to see that the client is in fact behind a NAT. It catches that now however I see this in my debug (ser):
ser[21770]: transaction was sent to a NATED client -> fix nated contact ser[21770]: ERROR: on_reply processing failed
Could the last error be a/the problem? Come on I know someone else has had this problem. Please help! NOTE: I just tested this out on Asterisk (as a client behind NAT) and got the same results. It's simply not changing the RTP IP address..
--snippet--
onreply_route[1] { # NATed transaction ? if (isflagset(6) && status =~ "(183)|2[0-9][0-9]") { log(1, "transaction was sent to a NATED client -> fix nated contact\n"); fix_nated_contact(); force_rtp_proxy(); # otherwise, is it a transaction behind a NAT and we did not # know at time of request processing ? (RFC1918 contacts) } else if (nat_uac_test("1")) { fix_nated_contact(); };
-----Original Message----- From: Matt Schulte Sent: Thursday, November 18, 2004 8:09 AM To: serusers@lists.iptel.org Subject: [Serusers] NATHelper + usrloc (+ rtpproxy?)
All,
This is my first post to this list so go easy on me. :-) I'm rather new to Ser, in fact I just installed it for the first time early in the week. I'm working on the NAThelper module to get traversal working, I have outbound (sip phone -> NATout -> ser) working just peachy, RTP works in both directions hooray. The question is I'm having problems getting RTP inbound, the ring of course goes through, and RTP from the NAT'd side of course works fine however getting back through the NAT (from outside) for RTP in this sense fails. Let me explain the setup:
I'm using the registrar, NAThelper, usrloc, and of course (Portaone's) RTPproxy modules. The current SIP phone is an SNOM (yes yes, I know..). The "endpoint" is Asterisk. When I do a sip debug on Asterisk, I see the RTP request however it's coming from the NAT'd fake address:
v=0 o=root 780961119 780961119 IN IP4 192.168.1.101 s=call c=IN IP4 192.168.1.101 t=0 0 m=audio 10004 RTP/AVP 0 a=rtpmap:0 pcmu/8000 a=sendrecv
I have an idea of what to fix just not sure how to fix it. Obviously we need it to goto RTPproxy, since this is "backwards" how would I get it to recognize the correct IP?
See my config below, most of it is ripped off of the NAThelper.cfg example. :-) Thanks all..
NOTE: All calls are destined for ${SIPDOMAIN}, in this case, the machines hostname. This is normal and intentional :-)
# ---- SNIPPAGE ---- modparam("rr", "enable_full_lr", 1)
# !! Nathelper modparam("registrar", "nat_flag", 6) modparam("nathelper", "natping_interval", 30) # Ping interval 30 s modparam("nathelper", "ping_nated_only", 1) # Ping only clients behind NAT # main routing logic
route{
# initial sanity checks -- messages with # max_forwards==0, or excessively long requests if (!mf_process_maxfwd_header("10")) { sl_send_reply("483","Too Many Hops"); break; }; if (msg:len >= max_len ) { sl_send_reply("513", "Message too big"); break; }; # !! Nathelper # Special handling for NATed clients; first, NAT test is # executed: it looks for via!=received and RFC1918 addresses # in Contact (may fail if line-folding is used); also, # the received test should, if completed, should check all # vias for rpesence of received if (nat_uac_test("3")) { # Allow RR-ed requests, as these may indicate that # a NAT-enabled proxy takes care of it; unless it is # a REGISTER log("LOG: Caught uac test 3 \n"); if (method == "REGISTER" || ! search("^Record-Route:")) { log("LOG: Someone trying to register from private IP, rewriting\n");
# This will work only for user agents thatsupport symmetric # communication. We tested quite many of them and majority is # smart enough to be symmetric. In some phones it takes a configuration # option. With Cisco 7960, it is called NAT_Enable=Yes, with kphone it is # called "symmetric media" and "symmetric signalling".
fix_nated_contact(); # Rewrite contact withsource IP of signalling if (method == "INVITE") { log("LOG: fix nated sdp\n"); fix_nated_sdp("1"); # Add direction=active to SDP }; force_rport(); # Add rport parameter to topmost Via setflag(6); # Mark as NATed }; };
# we record-route all messages -- to make sure that # subsequent messages will go through our proxy; that's # particularly good if upstream and downstream entities # use different transport protocol if (!method=="REGISTER") record_route(); # subsequent messages withing a dialog should take the # path determined by record-routing if (loose_route()) { # mark routing logic in request append_hf("P-hint: rr-enforced\r\n"); route(1); break; }; if (!uri==myself) { # mark routing logic in request append_hf("P-hint: outbound\r\n"); route(1); break; }; if (uri==myself) { if (method=="REGISTER") { log("LOG: Caught register, registering userin local db\n"); save("location"); break; };
lookup("aliases"); if (!uri==myself) { append_hf("P-hint: outbound alias\r\n"); route(1); break; }; log("LOG: Caught uri myself\n"); # native SIP destinations are handled using ourUSRLOC DB #if (!lookup("location")) { # sl_send_reply("404", "Do what now"); # break; #}; }; append_hf("P-hint: usrloc applied\r\n"); route(1);
}
route[1] { # !! Nathelper if (uri=~"[@:](192.168.|10.|172.(1[6-9]|2[0-9]|3[0-1]).)" && !search("^Route:")){ sl_send_reply("479", "We don't forward to private IP addresses"); break; }; # if client or server know to be behind a NAT, enable relay if (isflagset(6)) { log("LOG: Caught NAT flag 6 forcing rtp proxy\n"); force_rtp_proxy(); }; if (method=="REGISTER") { break; log("LOG: Caught Register down in our call routing, breaking\n"); };
#### Below is mostly my own doing #### if (method=="INVITE") { log("LOG: Caught INVITE \n"); if (lookup("location")) { log ("LOG: Caught registered invite, sending there\n"); # NOTE forcing rtp maybe bad idea for ALL users, this is # a quick fix (which doesn't work anyway!) #force_rtp_proxy(); #forward(uri:host, uri:port); #nor does this t_relay(); break; } else if (uri=~"^sip:[0-9]*@") { # ... forward to asterisk; forward(xxx.xxx.xxx.xxx, 5060); log("LOG: Tapping rowlf\n"); break; }; }; #### ####
t_on_reply("1"); if (!t_relay()) { sl_reply_error(); };}
# !! Nathelper onreply_route[1] { # NATed transaction ? if (isflagset(6) && status =~ "(183)|2[0-9][0-9]") { fix_nated_contact(); force_rtp_proxy(); # otherwise, is it a transaction behind a NAT and we did not # know at time of request processing ? (RFC1918 contacts) } else if (nat_uac_test("1")) { fix_nated_contact(); }; }
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Greger V. Teigre