Is anyone aware of an issue with Draytek routers where they drop (and block) Asterisk IAX traffic after some time? I've got two installations both using Draytek routers that experience the same problem where an IAX connection drops after a number of hours and refuses to re-connect, as if the remote port is firewalled somehow. Using a bit of iptables trickery to put IAX on a different port gets it going again, but then that port get blocked eventually too.

I first had this happen on a setup with a (<1 year old) 2820 and never worked out why it happened. I'd always assumed it was something mis-configured on the server.

However, at another installation, I've just replaced an older (maybe 5 years old) 2820 with a brand new 2830 and the problem has since started there. Everything else has remained identical, just the router has been swapped out.

Both installations are on different ISPs and have their own Linux box running Asterisk behind them so I don't think the problem is there. Fairly convinced it's the Draytek causing the issue, and it must be something in the newer firmware versions as the 5-year old 2820 is now in service at another site with Asterisk and running perfectly fine.

Is there any known issue here that I can fix in some way? Or a setting I need to change in the later firmware versions to prevent this happening?

Thanks, Chris

Any Draytek staff help with this or do I need to raise it with tech support?

I've also confirmed today that rebooting the router solves the problem, so now absolutely confident that it's the router at fault rather than anything else. Of course, it still times out after a number of hours.

Chris

the drayteks just dont play well with SIP traffic.
we are having ongoing issues with many customers who are using the 2820's and Snom PBX's.
at the moment we are in t he process of swapping out all the drayteks for billion routers just to avoid the ongoing issues.

there has been several suggestions as to why there is a problem but so far no one has really worked it out.
the only common factor is are the dreyteks.

Chris, can you check the arp table on the 2830 - see if its a similar issue to:

http://www.forum.draytek.co.uk/viewtopic.php?f=2&t=16436&p=69549&hilit=2830#p69549

My VoIP phones dissappear after 1-3 days from draytek 2830 arp table!! A reboot of 2830 fixes issue.

I have the same situation, pretty much. Two asterisk servers each behind a draytek, one 2820, one 2800. Sometimes after some weeks of operation it drops & blocks out. Will not reconnect. I run the connection over VPN, but I have also tried it with NAT too and it can do the same thing. Only choice is reboot the router.

Here's the odd thing: it used to do this when both ends were 2800 (same FW) but only one end was a problem.

Really hammering the router seems to break it. Also some connection drops & too much playing with the settings.

I have had SIP do the same to me (outbound over NAT to external provider) BUT I seem to have worked round that after I cleared out a load of unneeded SIP connections from my server. It particularly was aggravated by multiple sip connecions to the same end point.

My only conclusion was that it was a pointer leak somewhere in an internal table (ARP, NAT, Firewall, etc.) so that part of the router thinks the connection is up but sends the packet down a black hole. But that is just educated guesswork.

Ask for beta firmware from Draytek, they definitely have some that fixes the problems you're describing.
I'm guessing that the next release for the 2830 & 2820 isn't far away.