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New Member

Ping No Reply on certain IP


Hi all,


Currently I'm having on some ping no reply on only certain IP when ping to a NLB virtual IP.

Usually these IP which did not get reply from the NLB virtual IP are those host where their IP are assigned by DHCP.

A few SPAN port had been configured and wireshark have been done.

The NLB server did reply the ping.

Capture shows the ping reply did enter the Core Switch, however the ping reply did not exit the Core Switch to the WAN interface where the host is sitting.

Is there any other method to check on the Core Switch?

Some other  IP does not face this issue and packets were able to exit the Core Switch back to the host.



Hey,Would need switch details


Would need switch details, like model number, installed supervisor (in case of modular switch), running IOS and configuration.



New Member

Hey Rajeevsh, It seems that

Hey Rajeevsh,


It seems that the issue was due to an ACL blocking some of the traffics.

New Member

The address of NLB must be

The address of NLB must be inserted into the switch with this command :

mac address-table mac 000.XXX.XXX.XXX interface Giga1/0/1 Giga1/0/2

if your terminal servers are on the port Giga1/0/1 and Giga1/0/2 and the NLB mac address is a Multicast address

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