[Asterisk-Users] IAX pretending to see unreachable hosts and other weird things

[Benjamin on Asterisk Mailing Lists]

Hi

I'd like to share a weird and awkward experience...

I have an Asterisk server which connects to various other Asterisk
servers using IAX2 peering through IPsec tunnels.

Recently this server has started to show some weird behaviour. For
example, you would be able to dial out and the console would seem to
confirm that there was activity but Asterisk wouldn't actually do
anything other than give you a ringing feedback but not actually make
any attempts to connect.

I also noticed that I was able to see IAX peers which wouldn't see me.
Stop-starting Asterisk typically fixed these issues but the time until
those problems occurred again would become shorter and shorter.

Today, I had to take the VPN server down which means all those tunnels
through which this box connects to many of its IAX peers were not
available. Strange as it may seem, Asterisk claims to see those peers
even with varying latencies when you issue "iax2 show peers" multiple
times.

Those peers are definitely unreachable. Asterisk pretends to see them
just as it pretended to dial when it didn't really dial.

And now comes the weirdest part: I executed a "stop now" and it looked
like nothing happened as I am still at the console prompt. However,
checking in another terminal reveals that Asterisk has indeed shut
down, yet the console is still up taking my commands albeit not doing
anything.

This Asterisk server has been running virtually unmodified for about a
year. I am not going to bother trying to troubleshoot this any further
but instead I will rebuild it with a newer version of Asterisk. I am
however somewhat concerned about this because I live by the mantra "if
it's not broken, don't fix it" for systems other than play/lab/test
boxes. Here I have one of the longest running Asterisk boxes I look
after which was working prefectly and hasn't been changed nor has it
seen any increase in workload, yet it developed a kind of Alzheimer's
desease, looking alright on the outside, but totally braindead on the
inside.

The system has a total of 18 IAX peers and whilst call traffic is very
low, all of the IAX peers have qualify=yes so there is quite a bit of
IAX ping/pong traffic. One of the peers has been constantly
unreachable for at least three months. The box is a PIII 500MHz based
IBM with 256MB RAM. It's mostly using those IAX peers but has a single
X100P on which there are a few calls, mostly inbound.

I have other Asterisk servers with a similar number of IAX peers with
qualify=yes and on those I haven't seen anything that would suggest
that IAX ping/pong traffic and unreachable hosts may have a negative
impact on the server, but I would nevertheless like to ask if anybody
on the list has had any remotely similar experience that would suggest
system instability as a result of an increasing number of IAX peers
with qualify=yes.

I would also like to ask any of the developers working on IAX related
code what they think about the potential impact of IAX ping/pong
traffic on system health.

Hopefully this is just related to the rather dated version of Asterisk
on this box: CVS-11/09/03-13:18:45.

rgds
benjk

-- 
Sunrise Telephone Systems, 9F Shibuya Daikyo Bldg., 1-13-5 Shibuya,
Tokyo, Japan.

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