I have a small customer that is still nursing an XTS until they can afford a new phone system. They shrunk down to about 8 employees, two of which work from home. The 2 home phones are 7024D phones, and the 6 in the office are regular 3015 phones. The 2 IP phones connect in thru a LANB card.

This set up has worked fine for years now. Suddenly about a week ago, the 2 IP phones started locking up at the top of the hour, every hour. 8am, 9am, 10am, etc. The display looks normal but the speaker and hold/save buttons start flashing, and the phone is inoperable (no dial tone, buttons don't work, no calls come in). If they do nothing, the phones will come back to life after 10 minutes. If they unplug the phone and plug it back in, they get the "NO RESPONSE FROM MFIM" message, at which point if they unplug and replug one more time, then the phone starts working again. They don't need to cycle power on the KSU, but they have done that several times just for good measure, and that doesn't help.

This is one of the screwiest problems I've ever seen. I'm probably going to try swapping in a new LANB card, but I'm doubtful it will fix it. The fact that it's happening so regularly is what has me scratching my ass. I've never heard of a bad board that was doing abnormal behavior at regular intervals but works fine the rest of the time.

Anyone have any ideas?

This sounds to me more like an internet provider issue than a phone system issue, like there is a wide area network ip conflict somewhere and when the device signs on with the same ip as the lanb ip card then things go screwy. I have seen this happen before.

Thanks, Derrick. In my case, the LANB is programmed with an IP from the block of external IPs my customer got from FiOS years ago. Now if someone at FiOS assigned that same block to another customer a week ago (assuming the FiOS system will even let them do that), I would think the system would detect that pretty quickly. But as screwy as this problem is, I don't feel like I can rule anything out right now.

A network-related thought I had was there might be an app on the internet somewhere that sends a packet every hour, and the person who set up that app fat-fingered the destination IP address, and now my LANB card is getting it, and the packet messes up the LANB card. But I discounted that idea because of the IP phones coming back to life on their own 10 minutes later. One mystery packet coming in from the internet and screwing up the card I can easily see. But a second one coming in 10 minutes later and resetting the phones, that's pushing it.

I was hoping some LANB expert would chime in and say, "oh yea, the LANB cards have a timer built in that can sometimes turn itself on and run amok." Absent such a chime, I'll probably stick the LANB card behind a firewall. My recollection is that Vodavi equipment didn't work reliably with port forwarding, but it was okay with 1:1 NATing, so I'll set that up. I'll also block all ports except the VoIP ports. Maybe I'll get lucky and the problem will go away. If that doesn't do it, then it's time for Wireshark.

The lanb card won't reset itself, but the phones will. They usually keep polling the mifm until they make contact.

Have you turned a trace on and captured? Could it be a ddos attack? We had that happen at several sites and then it just up and quit one day, These weren't critical phones so when we ran the trace and saw the public IP address trying to connect to it we knew something was trying to log into it and bam the phones would go down.

Just a thought.

We have hundreds of Vpn users that have worked for years. Starting in August they have been logging off every hour. Seems to be with Comcast mainly. We ended up changing the encapsulation setting to overcome. https://forums.xfinity.com/t5/Your-Home-Network/Dropping-VPN-every-hour-Net-Neutrality/td-p/3139302