Netdump FAILED couldn't attach to dump server on ESXi 7.0.x.
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Netdump FAILED couldn't attach to dump server on ESXi 7.0.x.


Article ID: 312008


Updated On:


VMware vSphere ESXi


There are many reasons for this phenomenon. ThisĀ  article describes that due to configuration problems, that is, the vmknic used by netdump has more than one NIC teaming active Uplink device, which may cause this problem. Users will encounter failure in the case of a specific network and configuration.

During PSOD dump netdump phase, there are error messages in PSOD screen.
Starting network netdump from to
Netdump: FAILED: Couldn't attach to dump server at IP
Stopping Netdump.


VMware vSphere ESXi 7.0.x


The reason is, netdump preferentially uses the active Uplink device during configuration, but when netdump occurs, the active Uplink device in the actual teaming may have changed, so for external switches, this is a MAC drift, which may cause ESXi netdump to not receive a response packet within the expected time.


Currently there is no resolution.

The ESXi netdump process basically does not use multiple Uplink devices, do not configure multiple active Uplink devices for the vmknic used by netdump.