AD Server Duplicate Ping (DUP!) ?!

Question

Hi,

I have a Windows Server VM which when pinged sends (DUP!), read about it online and seems like a duplicate IP issue, but there is only 1 Server and 1 Firewall in the whole setup (its a test setup).

Can I know why this is happening, and how to fix it ?

Thank You

Answer 1

Hi @touqeeranjum ,

The DUP packets indicate that the ping command has received replies from the same IP address but with different MAC addresses.

You can shutdown temporary the server and launch a ping to check if there is another device configured with same IP.

ping -t x.x.x.x

If you don't any device with same IP , it should be related to your network configuration.

Here a similar case : VMware ping duplicates issue (DUP!)

Please don't forget to mark helpful answer

Answer 2

Hello

Thank you for your question and reaching out. I can understand you are having query\issues related to (DUP!) ping.

As Windows's (at least all current versions') TTL is 128, the ping responses are coming from your DC. The other device (likely Linux-based) that is sending ping responses with a TTL of 255 also has an A record in DNS that is identical to the A record for the DC. Examine the relevant DNS zone to identify the problematic an entry and remove it. Verify the system associated with the infraction A check to verify sure the IP address isn't the same as the DC's

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