Customer's Wierd DNS Problem

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  • Frank Hagan
    Senior Member
    • Mar 2004
    • 724

    Customer's Wierd DNS Problem

    I have a customer who changed ISPs, and is now having trouble connecting to any of the sites on his server here (including any of my other customer's sites). Other customers of the same ISP (their neighbors) are not having a problem.

    The weird thing is that when they do a tracert for their domain name, the IP address that it is looking for is the old Cpanel51 IP, 74.52.103.130. It should be resolving to Cpanel63, 74.86.90.185.

    The only thing I can think of is the local computer's hosts file. Any other possibilities? They had a new router installed when they went to the new ISP, but they swear they haven't changed any settings in the router.
  • AndrewT
    Administrator
    • Mar 2004
    • 3653

    #2
    Please submit a ticket with one of the domains that this problem is occurring on so that we can double check that it isn't a problem with the domain's DNS.

    Comment

    • Frank Hagan
      Senior Member
      • Mar 2004
      • 724

      #3
      Well, Andrew checked and there isn't a problem with the domain's nameserver set up. I had the customer try a tracert, and the proper server IP address comes up first, and the trace goes through to the Dallas datacenter, and then stops one hop away from the server IP address. And just times out.

      They have three computers doing this; the ISP is OK, as the neighbors can reach his site. He can take his laptop to his shop, also on the same ISP, and can connect with his laptop. But if he uses the laptop on his home network, he can't connect.

      Embarq, the ISP, uses a Zyzel 660 router/modem, and I am wondering if it has some kind of specific IP filter that has been activated. Anyone know anything about these?

      Comment

      • AndrewT
        Administrator
        • Mar 2004
        • 3653

        #4
        The source IP addresses are likely blocked, usually due to excessive failed login attempts. Please have them go to http://whatip.gzo.com/ and you should submit a ticket with their IP address from the location that they are experiencing problems.

        Comment

        • Frank Hagan
          Senior Member
          • Mar 2004
          • 724

          #5
          Andrew solved the mystery; their IP was blocked due to HTTP flooding. They just don't know how it was done, but I think it might have to do with web-enabled software on their desktop (they use Frontpage, and I suspect when they changed ISPs, they flooded the server as it was trying to reconnect).

          I had the same issue from my work system due to doing a copy/paste operation from WHM's "accounts list" into Excel. Excel promptly tried to log into Cpanel for each of my customers. You have to remember to use "Paste Special" and select text as the format; if you select HTML (the default for copied HTML), it will try to visit each of the Cpanel links, triggering the flood protection.

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