No internet after Virgin Modem disconnected/reconnected



  • I'm in the UK and I've recently changed to Virgin Media, all working well except I've noticed two issues which I've no idea how to resolve.

    1. If I disconnect/reconnect the patch cable from the router to the modem I loose internet connection
    2. If the modem updates I loose the internet connection

    The Virgin hub is in modem mode, when the above happens I have to reboot Pfsense only and it all works again.

    I've done some searching on here, and there is some similar but I don't know enough to confirm if its the same issues.

    To test things I simply disconnect/reconnect the patch cable, when I do this looking at pfSense dashboard all appears OK, the gateway widget shows my connection as up, the traffic graphs show a very small amount of traffic around the 1k mark, but I have no internet available. On the interface widget it shows my correct public IP as well.

    If I ping 8.8.8.8 (from PC or pfSense) then all packets are received, this is also set as my monitor IP. However any other address I ping then all packets are lost.

    I've attached a snippet of the system general log.

    Hopefully someone knows what the issue is, as its fine if I'm at home I can simply reboot it, otherwise I'll have the family on to me.

    Log.txt



  • try setting your router



  • Has nobody got any advice?

    @hardiktechie

    You registered just for that one post, which makes no sense at all or just states the obvious but doesn't say which setting  ::)



  • @Ronski:

    Has nobody got any advice?

    Instead of rebooting your Pfsense machine, just go to Status > Interface and release/get new IP…hope your modem is in bridge mode also. Why are you plugging and removing the cable?

    ![Screen Shot 2018-05-10 at 10.38.03 PM.png](/public/imported_attachments/1/Screen Shot 2018-05-10 at 10.38.03 PM.png)
    ![Screen Shot 2018-05-10 at 10.38.03 PM.png_thumb](/public/imported_attachments/1/Screen Shot 2018-05-10 at 10.38.03 PM.png_thumb)



  • Thank you very much for the reply

    Yes the modem is in bridge mode.

    When I was first connected to Virgin I didn't have a suitable length patch cable so used one that was far to long, then when my shorter one arrived swapped it over, and then no Internet.

    Obviously I'm not planning on changing cables again, but if the modem updates the firmware the same happens, I have no control over this so need the connection to come back up reliably afterwards in case I'm not around to sort it out.

    Any suggestions on achieving this automatically?



  • ????
    If a changing the cable caused the problem, then why wouldn't you replace the defective cable to fix the problem?  As for the first cable being long, Ethernet cables can be up to 100 metres long and I doubt you had one anywhere near that long.  Also, Ethernet cables are cheap.  If you suspect a problem with one, toss it and get another.  I've got dozens in my closet here.



  • Neither cable was defective, I just like a tidy installation -. I've already clearly stated why the cable was changed, and its pretty clear it was a new one, as I said when it arrived I changed it over.

    Forget the cable, but I still have the issue of losing internet if the modem firmware automatically updates.



  • No need to worry…firmware for your modem will not release every week...most likely it's once a year or once in two years. Actually, after the modem upgrades, it should automatically reboot...that in it self should issue a new IP or same IP dependent on how long of a lease period set by default. I set mine for three days.



  • Hopefully it won't be often, but it did update Saturday (Puma update) and and I lost the connection.



  • Virgin firmware updates usually reset the modem into router mode.  It depends how they configure the docsis system for updates.

    Consequently if pfsense is expecting modem bridge mode then your connection will fail, especially if you have static Wan IP on pfsense.  If your Wan is set for DHCP, then it will probably still have the old VM public IP from the bridge, so if the modem resets to router mode the pfsense wan cannot talk to the modem until the dhcp renews.



  • Thanks pwood999, when the firmware updated it came back up in modem mode and my wan is set to DHCP

    When my WAN is effectively down can anybody explain why I can ping 8.8.8.8 but no other IP address I've tried? See first post for details



  • @pwood999:

    Virgin firmware updates usually reset the modem into router mode.  It depends how they configure the docsis system for updates.

    Consequently if pfsense is expecting modem bridge mode then your connection will fail, especially if you have static Wan IP on pfsense.  If your Wan is set for DHCP, then it will probably still have the old VM public IP from the bridge, so if the modem resets to router mode the pfsense wan cannot talk to the modem until the dhcp renews.

    If the modem is in bridge mode, it shouldn't make any difference.  It's transparent and only not usable during reboot.  After that's completed, any current DHCP addresses should still work.  If the computer detects the reboot, via dropped Ethernet connection, it will make another DHCP request.  If it doesn't there will be a time when the connection fails, but then it should continue with the same address, unless the interruption was so long that the lease timed out.  A bridge mode modem rebooting should really be not much different than briefly unplugging the Ethernet cable.



  • @JKnott:

    A bridge mode modem rebooting should really be not much different than briefly unplugging the Ethernet cable.

    But that's the thing, if I briefly disconnect the WAN cable to the modem I lose internet, except the ability to ping 8.8.8.8 which works fine, any other IP I've tried fails. This is from within pfsense or from a connected PC.

    Pfsense thinks the connection is up, both the dashboard gateway widget and status/interface shows the status as up.

    @NollipfSense:

    Instead of rebooting your Pfsense machine, just go to Status > Interface and release/get new IP

    Going to Status > Interface and release/get new IP does not work either.

    I know I nor anyone else is going to be disconnecting the cables, but if there is a firmware update or maintenance somewhere else which affects my connection I'd like to know that it is reliably going to come back up, at the moment it is not.



  • But that's the thing, if I briefly disconnect the WAN cable to the modem I lose internet, except the ability to ping 8.8.8.8 which works fine, any other IP I've tried fails. This is from within pfsense or from a connected PC.

    Pfsense thinks the connection is up, both the dashboard gateway widget and status/interface shows the status as up.

    After rebooting pfSense, do you get the same address & subnet as before?  If not, then something else is changing and pfSense has no way to know.  As mentioned, normally the Ethernet connection is dropped on reboot.  This would cause the dhcp client to request an address again.



  • Yes, under status>interface before and after reboot the IPv4 address, subnet mask and gateway all remain the same.



  • You said you could ping 8.8.8.8, but not others.  Are you pinging those via host name or IP address?

    Still, this sounds like a modem problem.  I have rebooted my modem or disconnected it several times.  It just keeps on working.  The only issue I had was if I disconnected the Ethernet cable to the modem, I'd get a different IPv6 prefix, but that was fixed when a setting to not release the prefix was introduced.  IPv4 was never affected.



  • Thank you very much for taking the time to help with this, glad to say the problem is solved  ;D Your last post prompted me to try something.

    I powered off the modem and back on, once it came up I checked and had lost internet except for the ability to ping 8.8.8.8.

    I was pinging via IP address, and as I said before the only one that worked was 8.8.8.8 which was my gateway monitor IP address. So I changed the monitor IP for the gateway to 8.8.4.4 and could no longer ping 8.8.8.8 but could now ping 8.8.4.4.

    Whilst I was in Edit Gateway changing the monitor IP address I noticed a check box to make it the default gateway, ticking that fixed the issue once applied.

    Don't know if the behaviour I was seeing is expected behaviour or just some weirdness going on, either way I'm very pleased its sorted.

    Thanks to everyone that tried to help.