I’ve got a remote system that is plagued with a strange issue.
It happens from time to time. Yet, I’ve not found any condition that trigger this phenomenon.
Here is my setup:
– PSTN <---> ITSP <--SIP trunk--> Router <----> Switch <----> Asterisk box
– Asterisk box is a Raspi/Rasbian with Asterisk 1.8.13
– Switch is DLink DGS-1210-10P
– Router is Zyxel box (I don’t manage it)
I see (with Asterisk console) that Asterisk is sending OPTIONS/REGISTER
With tcpdump and wireshark, I see that :
1. those OPTIONS/REGISTER messages are sent to my ITSP gateway (IP src is Asterisk box, IP dst is ITSP gateway)
2. my router replies (within 30ms) with something Wireshark presents as an ICMP message like this:
ICMP 491 Destination unreachable (Communication administratively filtered) ( (IP src is router box, IP dst is Asterisk box)
While this happens, I can successively ping my ITSP gateway.
Searching the web, I found  and .
1. Is it common to get an ICMP reply to a SIP message ?
2. Any advice or suggestion ?