<div dir="ltr">My Previous message got high jacked due to Subject. Posting is again as a new thread. <br><br><pre>Hello,

I have two opensip servers, exactly same configuration, but one is acting
different. This is the call  flow.
Origination -- Invite------------&gt; Opensips
Origination &lt; 100 Trying ------ Opensips
 ---------------------------------------Opensips ----invite --&gt; End user
(freeswitch)
----------------------------------------Opensips &lt;--- 100 trying --
Freeswitch
----------------------------------------Opensips &lt;-- 183 Ringing --
Freeswitch
Keeps waiting and never forward 183 back to Origination.

While 2nd opensips works just fine/

MTU is 1500 on both.
Working Server versions
Centos 5.2, Openisps 11-2

Not working, version (Different OS, same version of Opensips)
Cent OS 5.4, Opensips 11-2

Below is the full trace. Any hint to fix this will big help. I am
suspecting fragmented packet size in 183 Session Progress, but not sure how
to fix it. If the packet is not fragmented all works fine.
<br>Did some more testing, if I route the call to another IP, that works fine. So something very specific to this IP only. <br>
This is original trace, ALL IPs has been modified for security.

 <a href="http://15.43.72.36:5060">15.43.72.36:5060</a> -&gt; <a href="http://29.16.115.170:5060">29.16.115.170:5060</a>
INVITE sip:<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">+13033334444 at domain.opensips.company.com</a>:5060;user=phone;transport=UDP;maddr=29.16.115.170
SIP/2.0.
v: SIP/2.0/UDP <a href="http://15.43.72.36:5060">15.43.72.36:5060</a>
;branch=z9hG4bKa83557bc149a92c4dd2e82551235a4d3.35f93e16.
Record-Route: &lt;sip:15.43.72.36:5060;lr&gt;.
Remote-Party-ID: &lt;sip:<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">+16784567634 at 52.88.1.5</a>
&gt;<i>;screen=yes;party=calling;privacy=off.
</i>f: &lt;sip:<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">+16784567634 at 19.73.4.24</a>:5060
;user=phone&gt;;tag=-45026-1a697ef-67d2935e-1a697ef.
t: &lt;sip:<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">+13033334444 at 52.88.1.5</a>:5060;user=phone&gt;.
i: b3338bd0185eadc713c41a697ef72c17e921839f4f01a344bb8-0091-7406.
CSeq: 1 INVITE.
Allow: ACK,BYE,CANCEL,INVITE,OPTIONS,INFO,SUBSCRIBE,REFER,NOTIFY,PRACK.
v: SIP/2.0/UDP <a href="http://52.88.1.5:5060">52.88.1.5:5060</a>
;branch=z9hG4bK0cba239efe292bb148db0d60f1938f42.4937234e;received=52.88.1.5.
v: SIP/2.0/UDP
IRW6:5060;maddr=19.73.4.24;branch=z9hG4bK-1a697ef-72c17e92-7809c98f;received=19.73.94.24.
Max-Forwards: 15.
m: &lt;sip:19.73.4.24:5060;transport=UDP&gt;.
k: 100rel, resource-priority, replaces.
c: application/sdp.
l: 235.
Record-Route: &lt;sip:52.88.1.5;lr&gt;.
.
v=0.
o=PVG 1453494628460 1453494628460 IN IP4 199.173.133.17.
s=-.
p=+1 6135555555.
c=IN IP4 199.173.133.17.
t=0 0.
m=audio 34552 RTP/AVP 18 0 8 101.
a=rtpmap:101 telephone-event/8000.
a=fmtp:101 0-15.
a=ptime:20.
a=fmtp:18 annexb=no.

#
U <a href="http://29.16.115.170:5060">29.16.115.170:5060</a> -&gt; <a href="http://15.43.72.36:5060">15.43.72.36:5060</a>
SIP/2.0 100 Giving a try.
v: SIP/2.0/UDP <a href="http://15.43.72.36:5060">15.43.72.36:5060</a>
;branch=z9hG4bKa83557bc149a92c4dd2e82551235a4d3.35f93e16.
f: &lt;sip:<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">+16784567634 at 19.73.4.24</a>:5060
;user=phone&gt;;tag=-45026-1a697ef-67d2935e-1a697ef.
t: &lt;sip:<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">+13033334444 at 52.88.1.5</a>:5060;user=phone&gt;.
i: b3338bd0185eadc713c41a697ef72c17e921839f4f01a344bb8-0091-7406.
CSeq: 1 INVITE.
v: SIP/2.0/UDP <a href="http://52.88.1.5:5060">52.88.1.5:5060</a>
;branch=z9hG4bK0cba239efe292bb148db0d60f1938f42.4937234e;received=52.88.1.5.
v: SIP/2.0/UDP
IRW6:5060;maddr=19.73.4.24;branch=z9hG4bK-1a697ef-72c17e92-7809c98f;received=19.73.94.24.
Server: Opensips SIP Gateway.
Content-Length: 0.
.

#
U <a href="http://29.16.115.170:5060">29.16.115.170:5060</a> -&gt; <a href="http://28.3.8.20:5060">28.3.8.20:5060</a>
INVITE sip:<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">13033334444 at 28.3.8.20</a>:5060;user=phone;transport=UDP SIP/2.0.
Record-Route:
&lt;sip:29.16.115.170;lr;ftag=-45026-1a697ef-67d2935e-1a697ef;did=c63.65dae2a5&gt;.
Via: SIP/2.0/UDP 29.16.115.170:5060;branch=z9hG4bK3a79.ead0d7c5.0.
v: SIP/2.0/UDP <a href="http://15.43.72.36:5060">15.43.72.36:5060</a>
;branch=z9hG4bKa83557bc149a92c4dd2e82551235a4d3.35f93e16.
Record-Route: &lt;sip:15.43.72.36:5060;lr&gt;.
Remote-Party-ID: &lt;sip:<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">+16784567634 at 52.88.1.5</a>
&gt;<i>;screen=yes;party=calling;privacy=off.
</i>f: &lt;sip:<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">+16784567634 at 19.73.4.24</a>:5060
;user=phone&gt;;tag=-45026-1a697ef-67d2935e-1a697ef.
t: &lt;sip:<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">+13033334444 at 52.88.1.5</a>:5060;user=phone&gt;.
i: b3338bd0185eadc713c41a697ef72c17e921839f4f01a344bb8-0091-7406.
CSeq: 1 INVITE.
Allow: ACK,BYE,CANCEL,INVITE,OPTIONS,INFO,SUBSCRIBE,REFER,NOTIFY,PRACK.
v: SIP/2.0/UDP <a href="http://52.88.1.5:5060">52.88.1.5:5060</a>
;branch=z9hG4bK0cba239efe292bb148db0d60f1938f42.4937234e;received=52.88.1.5.
v: SIP/2.0/UDP
IRW6:5060;maddr=19.73.4.24;branch=z9hG4bK-1a697ef-72c17e92-7809c98f;received=19.73.94.24.
Max-Forwards: 14.
m: &lt;sip:19.73.4.24:5060;transport=UDP&gt;.
k: 100rel, resource-priority, replaces.
c: application/sdp.
l: 235.
Record-Route: &lt;sip:52.88.1.5;lr&gt;.
.
v=0.
o=PVG 1453494628460 1453494628460 IN IP4 199.173.133.17.
s=-.
p=+1 6135555555.
c=IN IP4 199.173.133.17.
t=0 0.
m=audio 34552 RTP/AVP 18 0 8 101.
a=rtpmap:101 telephone-event/8000.
a=fmtp:101 0-15.
a=ptime:20.
a=fmtp:18 annexb=no.

#####
U <a href="http://28.3.8.20:5060">28.3.8.20:5060</a> -&gt; <a href="http://29.16.115.170:5060">29.16.115.170:5060</a>
SIP/2.0 100 Trying.
Via: SIP/2.0/UDP 29.16.115.170:5060;branch=z9hG4bK3a79.ead0d7c5.0.
Via: SIP/2.0/UDP <a href="http://15.43.72.36:5060">15.43.72.36:5060</a>
;branch=z9hG4bKa83557bc149a92c4dd2e82551235a4d3.35f93e16.
Via: SIP/2.0/UDP <a href="http://52.88.1.5:5060">52.88.1.5:5060</a>
;branch=z9hG4bK0cba239efe292bb148db0d60f1938f42.4937234e;received=52.88.1.5.
Via: SIP/2.0/UDP
IRW6:5060;maddr=19.73.4.24;branch=z9hG4bK-1a697ef-72c17e92-7809c98f;received=19.73.94.24.
Record-Route:
&lt;sip:29.16.115.170;lr;ftag=-45026-1a697ef-67d2935e-1a697ef;did=c63.65dae2a5&gt;.
Record-Route: &lt;sip:15.43.72.36:5060;lr&gt;.
Record-Route: &lt;sip:52.88.1.5;lr&gt;.
From: &lt;sip:<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">+16784567634 at 19.73.4.24</a>:5060
;user=phone&gt;;tag=-45026-1a697ef-67d2935e-1a697ef.
To: &lt;sip:<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">+13033334444 at 52.88.1.5</a>:5060;user=phone&gt;.
Call-ID: b3338bd0185eadc713c41a697ef72c17e921839f4f01a344bb8-0091-7406.
CSeq: 1 INVITE.
User-Agent: FreeSWITCH-mod_sofia/1.2.12+git~20130816T225403Z~8566ffa82a.
Content-Length: 0.
.

##########################
###############################
U <a href="http://28.3.8.20:5060">28.3.8.20:5060</a> -&gt; <a href="http://29.16.115.170:5060">29.16.115.170:5060</a>
SIP/2.0 183 Session Progress.
Via: SIP/2.0/UDP 29.16.115.170:5060;branch=z9hG4bK3a79.ead0d7c5.0.
Via: SIP/2.0/UDP <a href="http://15.43.72.36:5060">15.43.72.36:5060</a>
;branch=z9hG4bKa83557bc149a92c4dd2e82551235a4d3.35f93e16.
Via: SIP/2.0/UDP <a href="http://52.88.1.5:5060">52.88.1.5:5060</a>
;branch=z9hG4bK0cba239efe292bb148db0d60f1938f42.4937234e;received=52.88.1.5.
Via: SIP/2.0/UDP
IRW6:5060;maddr=19.73.4.24;branch=z9hG4bK-1a697ef-72c17e92-7809c98f;received=19.73.94.24.
Record-Route:
&lt;sip:29.16.115.170;lr;ftag=-45026-1a697ef-67d2935e-1a697ef;did=c63.65dae2a5&gt;.
Record-Route: &lt;sip:15.43.72.36:5060;lr&gt;.
Record-Route: &lt;sip:52.88.1.5;lr&gt;.
From: &lt;sip:<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">+16784567634 at 19.73.4.24</a>:5060
;user=phone&gt;;tag=-45026-1a697ef-67d2935e-1a697ef.
To: &lt;sip:<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">+13033334444 at 52.88.1.5</a>:5060;user=phone&gt;;tag=p5ZtZ40SSXprB.
Call-ID: b3338bd0185eadc713c41a697ef72c17e921839f4f01a344bb8-0091-7406.
CSeq: 1 INVITE.
Contact: &lt;sip:<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">+13033334444 at 28.3.8.20</a>:5060;transport=udp&gt;.
User-Agent: FreeSWITCH-mod_sofia/1.2.12+git~20130816T225403Z~8566ffa82a.
Accept: application/sdp.
Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER,
REFER, NOTIFY, PUBLISH, SUBSCRIBE.
Supported: timer, precondition, path, replaces.
Allow-Events: talk, hold, conference, presence, dialog, line-seize,
call-info, sla, include-session-description, presence.winfo,
message-summary, refer.
Content-Type: application/sdp.
Content-Disposition: session.
Content-Length: 249.
Remote-Party-ID: &quot;13033334444&quot; &lt;sip:<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">13033334444 at 52.88.1.5</a>&gt;;party=calli
# // Fragmented packet second part
U 28.3.8.20 -&gt; 29.16.115.170 <a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users">+32125 at 1480</a>:277
ng;privacy=off;screen=no.
.
v=0.
o=FreeSWITCH 1453563985 1453563986 IN IP4 28.3.8.20.
s=FreeSWITCH.
c=IN IP4 28.3.8.20.
t=0 0.
m=audio 21814 RTP/AVP 0 101.
a=rtpmap:0 PCMU/8000.
a=rtpmap:101 telephone-event/8000.
a=fmtp:101 0-16.
a=silenceSupp:off - - - -.
a=ptime:20.

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