Hi,
Date: Wed, 7 Sep 2011 09:44:34 +0200
From: Sa?l Ibarra Corretg?<[email protected]>
Subject: Re: [OpenSIPS-Users] nat_traversal: register keepalive not
engaging
To: OpenSIPS users mailling list<[email protected]>
Message-ID:<[email protected]>
Content-Type: text/plain; charset=iso-8859-1
Hi,
On Sep 6, 2011, at 3:29 PM, Gremaud Odin wrote:
Hello everyone,
I began using the nat_traversal module to create a NAT traversal dedicated box,
but I'm now stuck on something probably pretty stupid. Here is the design I'm
working with:
Public network || Private network
||
U1 -------> P1 -------> P2
||
||
U1 being the NATed UAC, P1 the NAT box and P2 an OpenSIPS Proxy/Registrar.
The registration process is OK, and I can even call another UA using U1. When checking
the proper functioning of my script, I noticed that I could not call U1 from any other
UA: indeed, the register keepalive did not trigger properly (no keepalive engaged for
REGISTER, even if it pass on the function). The keepalive mechanism is working fine with
INVITE (did not try with SUBSCRIBE), I traced OPTION messages going to U1 (which replies
with a "404 Not Found", is this normal?). I double-checked using the module
statistics, and there was no register keepalive, but during an dialog, it effectively
shows that U1 is keepalived. I traced the registration process for a possible error, but
the request is correctly transfered to P2, which responds with a 200 OK that P1 receives
correctly. I have no more ideas about what I'm missing here...
If it can help, here is the NAT and registrar process I use:
### NAT DETECTION ###
force_rport();
# Avoid NAT detection if source IP is local
if ( client_nat_test("8")&& $si!~"^10\.0\.0\.[0-9]{1,3}$") {
fix_contact();
append_hf("NAT-Scope: nat-relay\r\n");
# For initial invites and all subscribe
if ((is_method("INVITE")&& !has_totag()) || is_method("SUBSCRIBE")) {
nat_keepalive();
# For registers
} else if (is_method("REGISTER")) {
nat_keepalive();
append_hf("NAT-Received: $source_uri\r\n");
}
setflag(5);
}
### REGISTRAR ###
if (is_domain_local("$fd")&& is_method("REGISTER")) {
append_hf("Supported: Path\r\n");
add_path_received();
force_send_socket(10.0.0.1:5060);
t_relay("10.0.0.2:5060");
exit;
}
### RELAYING ###
# The request was processed by the proxy/registrar
if ($hdr(NAT-Scope)=="nat-relay"&& !isflagset(5)) {
#$du = $hdr(NAT-Received);
$fs = $keepalive.socket($du);
# Not a subsequent message (REGISTER, SUBSCRIBE or initial INVITE), avoid
looping on P2
} else if (!has_totag()&& $si != "10.0.0.2") {
$du = "sip:10.0.0.2:5060";
$fs = "10.0.0.1:5060";
}
if (!t_relay("0x03")) {
sl_reply_error();
}
Any advice or idea is welcome :)
I see you call fix_contact for any type of request. Don't do this for REGISTER
requests or you'll save the wrong received information. For a REGISTER just do
force_rport() and nat_keepalive().
Also, the NAT test you are doing seems wrong. If an endpoint puts his own
public IP address in the Contact header it will pass your test and no keepalive
will be done. I usually use 3, and in the case I mentioned before the endpoint
would fail test 2, because it would have a private address in the topmost Via.
Regards,
--
Sa?l Ibarra Corretg?
AG Projects
Thanks for the reply. I'm tired to be that dumb ;) I was looking
everywhere, but I didn't even notice that. It solved my issue concerning
the keepalive on register.
I know that my NAT test is not right, but this was for an
experimentation purpose: the lab I'm using is completely local and I do
not have any public address anywhere. So this did the trick with a NATed
virtual machine connecting to a non NATed network. I was planning on
using 3 also with a classic implementation.
Thanks a lot again for your reply, I can now proceed further on :)
Regards,
Odin
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