[asterisk-users] SIP port blocking

[Dovid Bender]

Darryl,

We had this with a large ISP in the US. They blamed it on a software bug. For this reason we offer clients the option to use a non standard port. It's most likely your ISP that is blocking the port for g-d knows what reason.

Regards,

Dovid

-----Original Message-----
From: Darryl Moore <darryl at moores.ca>
Sender: asterisk-users-bounces at lists.digium.comDate: Thu, 14 Apr 2016 17:48:02 
To: Asterisk Users Mailing List - Non-Commercial Discussion<asterisk-users at lists.digium.com>
Reply-To: Asterisk Users Mailing List - Non-Commercial Discussion
 <asterisk-users at lists.digium.com>
Subject: [asterisk-users] SIP port blocking

Hey all. This isn't directly an Asterisk question, but it is Asterisk 
related because I am using SIP on asterisk.

The last couple of days I found that our asterisk box was having all 
packets originating from port 5060 being blocked.

If I moved my SIP port to any other port I could register and place 
calls, leaving it on 5060 I can do neither. Also if I ran tcpdump on 
both ends of my truck connection. I could see all packets arriving at 
the other end ONLY when they were not originating from port 5060.

The next question was where was it being blocked. running traceroute 
yielded the following:

root at 1940IronStone:~# traceroute -z 1000 -A -U -p 5060 --sport=5060 
70.xx.xx.200
traceroute to 70.xx.xx.200 (70.xx.xx.200), 30 hops max, 60 byte packets
  1  192.168.1.1 (192.168.1.1) [*]  3.837 ms  5.282 ms  6.280 ms
  2  64.230.199.2 (64.230.199.2) [AS577]  9.690 ms * *
  3  64.230.232.177 (64.230.232.177) [AS577]  24.936 ms * *
  4  agg2-toronto63_xe5-1-0.net.bell.ca (64.230.156.178) [AS577] 40.235 
ms * *
  5  lns9-toronto63_GE1-0_101.net.bell.ca (64.230.103.145) [AS577] 
10.382 ms * *
  6  * * *
  7  * * *
  8  * * *
  9  * * *

Notice the second and third packet at each hop after the first router 
all timeout. Even when I put a long delay between packets. Looking 
further, I find the same response no matter what source port I use. It 
appears any UDP packet stream from the same port is being blocked.

I don't see this behaviour if I allow traceroute to use random source 
ports for each packet, and I don't see this on other networks.


traceroute  -A -U -p 5060 70.xx.xx.200
traceroute to 70.xx.xx.200 (70.xx.xx.200), 30 hops max, 60 byte packets
  1  192.168.1.1 (192.168.1.1) [*]  62.783 ms  62.759 ms  62.743 ms
  2  64.230.199.2 (64.230.199.2) [AS577]  66.565 ms  66.550 ms 66.587 ms
  3  64.230.232.177 (64.230.232.177) [AS577]  66.488 ms  66.487 ms 66.535 ms
  4  agg2-toronto63_xe5-1-0.net.bell.ca (64.230.156.178) [AS577] 66.521 
ms  66.510 ms  66.552 ms


Has anybody seen anything like this before? I'm going to send this to 
the ISP, but I thought I'd find out if anybody else had ever run into it.


Thanks,
Darryl


-- 
_____________________________________________________________________
-- Bandwidth and Colocation Provided by http://www.api-digital.com --
New to Asterisk? Join us for a live introductory webinar every Thurs:
               http://www.asterisk.org/hello

asterisk-users mailing list
To UNSUBSCRIBE or update options visit:
   http://lists.digium.com/mailman/listinfo/asterisk-users