Loss of Internet access after cable provider changes IP



  • Hi, I run a couple of networks on pfsense boxes that are on Montreal's Videotron Internet service. The IP address is supplied via DHCP. I use a Cloudflare Dyn address system to maintain connectivity to the sites.
    However, everytime the provider rolls the IP, we loose internet access.
    Can anyone shed some light on any tweak or setting I should look at to prevent this loss ?
    thanks

    Chris


  • LAYER 8 Netgate

    How are they "rolling" the address? What is done by their gear to let the CPE know it has to reacquire an address?



  • Its a cable internet service that offers IP adress via DHCP to the client, but dynamic IPs, so they can roll the IPs whenever their network requires it. I just made a change in the Advanced/miscellaneous area to "Flush all states when a gateway goes down". Generally when we loose connectivity a reboot fixes the issue. I have also had success with resetting the states from the Diagnostics menu so I am thinking this may have been the issue.
    commnents ?


  • LAYER 8 Netgate

    What I am saying is if they just change your address, they have to do something to make the WAN interface know the lease is no longer good. If they wait for you to renew, then offer you another address, everything will work.

    They can't just make your existing lease stop working and expect the WAN port to magically renew the lease.

    I would suspect a simple edit/save of the WAN interface would fix this without rebooting.

    This sounds like another case of an ISP doing something stupid.



  • I can understand getting a new address when you bounce your modem. I have a hard time seeing a practical reason for them to yank your address and assign a new one in the middle of the day just because, and to do so on a regular basis. I've heard about where they might do that routinely to consumer accounts so that anyone hosting a server has to screw around with changing IPs but I didn't know if that was an urban legend or not. I can definitely assume that they would rather have you paying for a business account with a dedicated IP address.

    Otherwise, I'd be calling them and angrily asking them why they keep screwing around with you and how you have to reboot your router just to get access back, and why do they need to keep doing this? No doubt you will get a canned BS response, but maybe not.



  • @KOM said in Loss of Internet access after cable provider changes IP:

    I can understand getting a new address when you bounce your modem. I have a hard time seeing a practical reason for them to yank your address and assign a new one in the middle of the day just because, and to do so on a regular basis.

    Also, unless the subnet changes, it should still keep working with the old address. I'm on DHCP with a different provider and my address is so stable it's virutally static. Also, the OP should check the host name for his IP. If it's based on MAC addresses, as mine is, then he doesn't need a dynamic DNS, as the host name will never change, unless he changes hardware. He can use the host command in pfSense to check the host name for the IP address.


  • LAYER 8 Netgate

    Also, unless the subnet changes, it should still keep working with the old address.

    That depends on what filtering the ISP is doing. There could very well not be a route for that address any longer. ISP networks are often not just a flat broadcast network like a normal subnet but are put through subscriber management systems, DHCP snooping tricks, OSPF, etc.



  • @Derelict said in Loss of Internet access after cable provider changes IP:

    That depends on what filtering the ISP is doing. There could very well not be a route for that address any longer. ISP networks are often not just a flat broadcast network like a normal subnet but are put through subscriber management systems, DHCP snooping tricks, OSPF, etc.

    Unless they have specific filters to block an address, routing will still take the packets to the subnet. At that point ARP and MAC addresses kick in for delivery to the user. OSPF is used to set up routing tables, not actually route the packets. The tables describe routing to the subnet, not individual hosts. Further, there shouldn't be any DHCP traffic, until the client renews the lease. At that point, the ISP may provide a different address.

    BTW, Videotron is a TV cable ISP. They'd have CMTS at the head end, which connects to the nodes in the neighborhood. Everyone on the CMTS will have the same subnet, though there may be multiple subnets for different services, etc..


  • LAYER 8 Netgate

    It would not surprise me - at all - if the old address was no longer usable if the ISP decides that is to be the case.



  • @Derelict Sorry for the confusion, the issue was NOT ip address change. It was a faulty Ethernet port on the Cable company's modem. Changed port, reset everything and it is working. Speaking to the tech that was troubleshooting, he kept saying that my cable was disconnected. So I returned to the site and when moving the cable in the connector, the link light would go off !! Changed ports and it works. Thanks for the input and assistance.



  • @claferriere

    One thing I learned many years ago, suspect cables and connectors first, as they often fail.


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