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So Internic sent over a few cs, and it seems fine on some of them. However, on some I have to run arping -U on to get them up and they only seem to stay up for a short time. They are a /24 properly bound via the ifcfg-eth0-range scripts.

Problem is if I don't leave the arping program on, they don't stay up!


The box is Centos 5.x.

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Unless you believe only people who know what "cs" is will be able to answer this question, you may want to add a lot more explanation to your question. – Johan Mar 15 '13 at 7:24
up vote 3 down vote accepted

It sounds like there may be an IP address conflict on the local network. If two devices have the same IP address, it'll be down to chance which ARP reply is honoured by other hosts.

To test this, try this:

  • disconnect the host you're having trouble with
  • delete its IP address from another host's ARP table (on Linux, arp -d [address])
  • ping the IP address from that host
  • look at the arp table and see if there is a matching hardware address

If there is, even if you don't get a ping response, some other host on your local network has that address.

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