Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm having a weird issue. On one of a mac, I noticed it was having some weird issues communicating with the server. I pinged the server,, from the terminal on the mac, and here are the responses I am seeing.

64 bytes from icmp_seq=0 ttl=64 time=0.457 ms
64 bytes from icmp_seq=0 ttl=255 time=4.753 ms (DUP!)
64 bytes from icmp_seq=1 ttl=64 time=0.459 ms
64 bytes from icmp_seq=1 ttl=255 time=4.716 ms (DUP!)
64 bytes from icmp_seq=2 ttl=64 time=0.288 ms
64 bytes from icmp_seq=2 ttl=255 time=4.742 ms (DUP!)

Why would two devices be responding to these pings?

share|improve this question
Does the machine with the IP-address maybe have configured as a secondary address? Although this still would be kinda wonky. – Alexander Janssen Oct 3 '12 at 17:54
Is the server NIC teamed? – joeqwerty Oct 3 '12 at 18:18
Let me guess -- you're trying to talk to a Microsoft Exchange system, and the client access servers are using Network Load Balancing? – jgoldschrafe Oct 3 '12 at 18:23
The server has two ethernet interfaces, each with their own IP addresses.. and It's a Mac OS X server. – Brett G Oct 3 '12 at 18:56

are you sure it's two devices, try arp -a command to list your arp table and see if both ip address are mapped to same mac address in it.

If you're sure they are different devices with different MAC addresses you can try and delete the arp table with arp -d -a or just one or both addresses with arp -d x.x.x.x an let them repopulate again.

Notice: I could be wrong with the syntax off arp command on macos, it's been a while since I did anything on it.

share|improve this answer
I did try arp -d * earlier and I was still seeing the same – Brett G Oct 3 '12 at 18:53
what is the ip and subnet mask on the client you're pinging from. Also are you on wireless or on cable, can you try connecting that client to some other switch – rAlen Oct 3 '12 at 19:32

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.