Anyone familiar with "603 Decline" SIP errors?

Our IPedge was working fine then suddenly stopped accepting inbound calls & VM went to "camp-on". Packet inspection showed constant "603 Decline" SIP errors for inbound calls & VM ports. Seemed like something was consuming all available ports. Oddly, when the entire system was rebooted everything worked fine for a few minutes but then quickly failed with 603 errors.

Seems like a PBX problem but we've had similar inbound call problems before & it's always due to our carrier. So I opened a ticket with them & it turns out they'd worked on a circuit that we are part of that morning. They said testing revealed no problems on their end. But when I got to work this morning, everything is working fine.

Has anyone else experienced this or know what's going on?

TIA!

You are being hacked. Try to secure the router and close as many ports as you can. Restrict the port 5060 to accept request only from you SIP provider ip address. What version of IPedge are you running?

That's not good

I'll take a look at the router & firewall settings. It's an odd coincidence this would happen on the same day the carrier worked on "our" circuit. Seems like we would have run into this long before now. Could it be our carrier was allowing traffic that it normally doesn't allow because I'm not seeing anything unusual today. Hmmm.

We're on 1.6.2.212.

Thanks a lot for your reply!

Hey, MarcO. Just curious why you asked about our version. Is there some vulnerability or something I should be aware of?

Thanks!

Doesn't matter which software version you are running if you get brute force attacked on port 5060 it will cause the SIP Converter service to fail.

Lock up the UDP 5060 so it can only come from your SIP trunk provider's IP address.

I've been combing through our firewall rules & it ain't pretty. Don't know what these guys were thinking. But you guys are correct that our firewall rules needed to be rewritten.

Thanks for sharing your knowledge!