Dropped connection very often, new IP allocated, in NG7 (Nottingham) area
 

Hi.

Since about the start of November, I've been noticing this problem. It can happen every 2 hours, every 3 hours, or sometimes not for 6+ hours, but usually a few times per day my connection to the internet is dropped.

I have noticed that this *always* happens at around a quarter to the hour. Then my dhclient kicks in and reconnects, and a bunch of shell scripts are triggered to fix stuff. Normally, though, if it were a problem with my network, I would expect it to pick up the same IP as it had had previously, as no lease ever has time to expire naturally. This is not the case, and a new IP is assigned, on a different net-block to the previous IP, which I think means that I have connected to a different NTL router.

I asked NTL's tech support who duly asked me for my modem's MAC address, went in and had a look. He said that he couldn't see a problem, and that I should call back next time it happens. Which would mean killing dhclient and sitting around waiting to fall off the net. It is perhaps worth noting that it happens most often at night, from 23h45 on. He also asked if I was running Kazaa or WinMX, which I'm not.

Does anyone have any idea why this would be happening? Have NTL got something that checks something or other at a quarter to the hour, and boots some people off whatever router they are connected to, making them find another one and thus have a new IP address?

It last did this at 23h45; it is now 0h45 and has done it again. My shell scripts should kick in and get me back online with working NAT and firewall within five minutes, allowing me to actually post this message :)

My network is as such: long NTL wire to the Terayon modem, then cat5 to a computer running freebsd5.3 which handles NAT, firewall, etc, more cat5 to a switch/hub, yet more cat5 to two desktop computers running Windows XP.

If anyone has experienced similar things, I'd love to hear about it. Especially if you found a way to make them stop.

Or if anyone can shed any light on why this could be happening.

Thanks.

Re: Dropped connection very often, new IP allocated, in NG7 (Nottingham) area
 

No, because in order to change routers your entire area has to be physically relocated onto a new one, which is done a) rarely and b) in the middle of the night. You can get a new IP at any time, DHCP being DHCP, but in practice it shouldn't change that often. Are the two IPs in the same range?

If you PM me your modem's MAC address (better not be your BSD machine IP if it keeps changing) I'll check it again. I'm one of about two people in ntl with a FreeBSD 5 on the desk (probably)!

Re: Dropped connection very often, new IP allocated, in NG7 (Nottingham) area
 

Are you sure your firewall is allowing dhcp renewal requests through ?

Re: Dropped connection very often, new IP allocated, in NG7 (Nottingham) area
 

Ports 67 and 68 (UDP) are set to 'pass', in and out. So that should be fine.