Argh! This is what happens every day to my DSL connection, at half past 12:
13 Mon Apr 10 12:26:53 2006 PP12 -WARN SNMP TRAP 2: link down
14 Mon Apr 10 12:26:53 2006 PP12 INFO ppp_ready: ch:8056167c, iface:80419f14
15 Mon Apr 10 12:26:53 2006 PP12 -WARN SNMP TRAP 3: link up
26 Tue Apr 11 12:26:46 2006 PP12 -WARN SNMP TRAP 2: link down
28 Tue Apr 11 12:26:48 2006 PP12 INFO ppp_ready: ch:8056167c, iface:80419f14
29 Tue Apr 11 12:26:48 2006 PP12 -WARN SNMP TRAP 3: link up
38 Wed Apr 12 12:26:56 2006 PP12 -WARN SNMP TRAP 2: link down
40 Wed Apr 12 12:26:58 2006 PP12 INFO ppp_ready: ch:8056167c, iface:80419f14
41 Wed Apr 12 12:26:58 2006 PP12 -WARN SNMP TRAP 3: link up
50 Thu Apr 13 12:27:00 2006 PP12 -WARN SNMP TRAP 2: link down
52 Thu Apr 13 12:27:03 2006 PP12 INFO ppp_ready: ch:8056167c, iface:80419f14
53 Thu Apr 13 12:27:03 2006 PP12 -WARN SNMP TRAP 3: link up
Worse than that, it will generally assign a different IP address to the connection when it reconnects! This buggers up any applications that rely on long-lived TCP connections, such as SSH shell logins, tunnels, remote-desktop sessions, and instant messaging; all get disconnected and have to be manually re-set up.
Initially, I thought this may have been a flaky connection. However, it appears not — check out those timestamps; that’s a scheduled, daily event. Also, there have been no other disconnections apart from those.
A discussion on the IIU mailing list revealed the reason — it seems BT Ireland have a policy of resetting their customers’ connections daily. That could be OK, if they came right back up with the same IP — TCP/IP is designed to cope with that, and generally does — but it does not do that. Instead the IP address is reassigned every single time.
This is turning out to be quite a nuisance. Working over the internet requires quite a few VPN connections, tunnels, and remote logins, and having to re-set those up, daily, is turning out to be a pain in the neck.
I’m casting around for hacks to get around this. Right now, I have an assortment of jiggery-pokery involving ssh, a shell script ‘while’ loop, and screen(1), but it’s messy and not working out too well. Ideally, I’d set up another VPN (via IPSec or CIPE), and set it up to reconnect on link failure, then route all other VPNs and remote logins out via that — but I don’t have spare routable IPs to do this with. Anyone got any good suggestions?
By the way, it’s worth noting that their FAQ fails to mention this, instead giving some incorrect information about my IP being ‘removed’ when my web browsing session ends:
Is it a fixed IP?
No, the product is set up with dynamic IP Addressing. This means that every time you open your browser you will be allocated a different IP address for the duration of that session. When the session ends the IP Address is removed.
That is incorrect — this has nothing to do with web browsing sessions.
To be honest, I’d prefer not to have to switch ISPs to get away from this brokenness — the rest of the service is quite nice, good pings, good throughput, no other disconnections or outages — but this is quite a problem for someone using BT Broadband for telecommuting purposes. :(
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