Still don't really understand it as I have now had three different IP addresses since changing the router.

New router solves the NAT loopback problem, but you answer would suggest it has caused the line to be unstable in some way?

Maybe the new router has caused the line to re-train or something?

Yep: Shell Energy BB via Technicolor TG582N as per my signature.

Router was supplied to me by New Call Telecom five years ago and worked fine with Plusnet, Sky and NowTV BB. Think I might have also used it with EE for a few months, but .....

Check the logs in the router to see if there are resync events or if the session is being disconnected. That might give a clue as to what is happening - maybe it is just an unstable router.

Can't see anything.

My point was the previous (TG588 supplied by Shell) router was the same for a few weeks. so I don't think it is a router issue.

It's all DHCP so it's all the same. Asking for a renewal of a lease can be denied by the server whether it is LAN or WAN. A disconnect can result in a change of IP address whether it is LAN or WAN.

It's all down to how the DHCP server is configured. I could easily make a LAN DHCP server look like one from an ISP because fundamentally they are highly likely to be the same piece of software.

It may not be a router issue but if there are logs that would help to see what is happening. Without logs it is guesswork. At the least does it tell you the uptime of the link and session? That would give an idea of whether the link is disconnecting - the question that would follow then is why but without logs we are probably going to have random chance to guess the answer to that question.

There are logs, but they contain nothing useful. e.g. :-

Jan 3 19:13:07 LOGIN User Administrator logged in on [HTTP] (from 192.168.1.67)


Info Jan 3 18:37:49 IDS fragment parser : fragment out-of-order (1 of 2) : 199.6.1.30 89.243.x.x 1492 UDP 53->11798 frag 23211:1472@0+


Info Jan 3 17:50:53 LOGIN User Administrator logged in on [HTTP] (from 192.168.1.67)


Warning Jan 3 17:50:38 IDS proto parser : tcp data on syn segment (1 of 1) : 192.168.1.67 17.252.11.246 0298 TCP 62869->443 [S.....] seq 2754500809 win 65535


Info Jan 3 16:28:44 IDS fragment parser : fragment out-of-order (1 of 6) : 149.20.64.3 89.243.x.x 1492 UDP 53->40479 frag 50761:1472@0+


Warning Jan 3 14:26:18 IDS proto parser : tcp data on syn segment (1 of 1) : 192.168.1.67 17.252.11.246 0298 TCP 61957->443 [S.....] seq 532413401 win 65535



Uptime: 1 day, 4:06:33

Does the uptime of 1 day, 4 h, 6m, 33s coincide with the last time the IP changed or has it changed more recently than that?

Good question.

Last (on Linux server) shows first log in with new IP as Tue Oct 22 13:49 - 13:50 (00:00)

Have to post this and look back at date and time my post with uptime was posted.

Edit: Wed 23-Oct-19 13:00:28.

So answer is 1 day 50 mins, looks about right.

Edited by hk11 (Wed 23-Oct-19 18:12:46)

It suggests the IP change is just a side effect of a resync. What you need to try and find out is why the line keeps resyncing - the fact it has started happening more on changing the router means either it is the router or changing the router has triggered something else (like DLM to become more active).