BT’s daily disconnects, revisited

As I noted last year, BT, the ISP I use here in Ireland, disconnects broadband sessions on a daily basis, assigning a new IP address; this is really aggravating to anyone who uses a VPN, such as most telecommuters. Reportedly, this is done to work around deficiencies in their billing system.

A comment from Jeremy on that post suggested something interesting, though:

Just had a very helpful tech support guy on from BT. [… he] told me to restart the modem sometime that will make it convenient for the 24 hour IP change – i.e. restart it at 6am, and then it’ll change IP every day at 6am.

I’ve tested this, and it works. Much more convenient! Now the renumbering and VPN breakage can take place when I want it to — at the start of the workday, instead of some random point chosen by BT’s billing system. Quite an improvement.

To make this useful, here’s a script, “reboot-zyxel”, which will reboot your Zyxel P-660RU router remotely over the LAN. (It requires perl and curl.)

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  1. Steve Loughran
    Posted March 2, 2007 at 14:47 | Permalink

    …I have one of those little timer-plugs, normally used to turn lights on at night, set up to restart my DSL router every night. No need for the rest of the infrastructure, and very reliable -except when trying to SSH home from the US, when there’s no way to disable it….

  2. Posted March 2, 2007 at 15:03 | Permalink

    Am I missing something, or is this exactly the half-solution Erik proposed in the first comment to your old post … ?

  3. Posted March 2, 2007 at 15:20 | Permalink

    Aidan: yes, actually, I guess it is. ;)

    At the time, though, I didn’t realise that if I performed the disconnect myself, it’d inhibit their own disconnect timer. it wasn’t until Jeremy asked that we figured that would be the case for BT’s setup too…

  4. Posted March 3, 2007 at 20:59 | Permalink

    Actually this is a perfect scenario for OpenVPN. Connections/sessions open over that should survive the disconnect and IP change. Cisco and other crappy solutions will not survive.

  5. Posted March 4, 2007 at 13:39 | Permalink

    Toby — interesting. I had OpenVPN pegged as just another IPSec implementation, and IPSec is allergic to NAT, IP changes and what-not… it seems I was wrong there.

  6. Posted March 4, 2007 at 15:58 | Permalink

    I should have mentioned, I use it over UDP, which should help.

  7. Wonga
    Posted March 4, 2007 at 18:58 | Permalink

    “Cisco and other crappy solutions will not survive” – I dont think Cisco are so bad.

  8. Posted March 5, 2007 at 04:39 | Permalink

    Re: Cisco – The WebVPN is really just a toy; and – based on my experience with the VPN client – if you can get it to run at all – it will not survive outages of internet service. This is of particular importance if you’re trying to do remote sysadmin (ssh). Connections over OpenVPN will.

  9. Posted March 7, 2007 at 13:00 | Permalink

    Hey, nice post. I was beginning to get head wrecked with all this IP changing that was going on!

    Thanks for the heads up!

  10. Ciaran
    Posted February 3, 2008 at 19:20 | Permalink

    Hi there

    I am using OpenVPM over a BT residential connection and I seem to be having a lot of problems with the VPN working for a few minutes and then dying. Usually like this:

    “Sun Feb 03 18:05:20 2008 NOTE: This connection is unable to accomodate a UDP packet size of 1573. Consider using –fragment or –mssfix options as a workaround.”

    I do have the following setting in my config file: mssfix 1450

    I have a Zyxel wireless router and I was wondering is there anything I should have specifically set in there to make sure my OpenVPN works as well as possible?


  11. Posted June 26, 2008 at 16:00 | Permalink

    I decided to make a petition! Im have had good luck with them in the past.

    If bt are going to loose 100k a year, they might stand up and take action.

    Please sign it!!


  12. Posted June 27, 2008 at 11:00 | Permalink

    hi Paul — I’d love to sign your petition, but I’ve already left BT anyway, partly because of this bug. so it’s too late for me ;)

  13. Posted June 27, 2008 at 11:56 | Permalink

    ah well! I am considering leaving BT also, but i have to find a similar deal aswe get with them!! thanks for the comment anyway, and letting me spam your blog with the link