VMware Employee
VMware Employee

vmk interface can ping each other between ESXs, but vm can't ping each other

TOPO:

vm1 ------------- esx1 ---------------------- ESX1 ----------- physical switch --------- ESX2 ----------- esx2 -------------------- vm2

192.68.1.1       vmk: 101.0.0.128                                                                                              vmk: 101.0.0.130       192.68.1.2

esx1 as a VM of ESX1

esx2 as a VM of ESX2

esx1 vmk interface is vxlan, IP: 101.0.0.128

esx2 vmk interface is vxlan, IP: 101.0.0.130

Question:

esx1 vmk could ping esx2 vmk

but vm1 can't ping vm2, why?

Analyze:

When vm1 ping vm2, I can capture the arp request packet send by vm1 on ESX1 vmnic, the packet has encapsulate vxlan header. The outer dest IP is 101.0.0.130.

But on ESX2 vmnic, I can't capture the arp request packet with vxlan header.

When esx1 vmk ping esx2 vmk, the packet source IP is 101.0.0.128 and dest IP is 101.0.0.130; when vm1 ping vm2, the arp request packet source IP is also 101.0.0.128 and dest IP is 101.0.0.130

Why the vm1 can't ping vm2?

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1 Reply
VMware Employee
VMware Employee

guow

Have you set the do not fragment flag and size to 1572 to ensure MTU is good on the underlay?

ping ++netstack=vxlan -I vmkX y.y.y.y -d -s 1572

X = vmk interface #

y.y.y.y = remote vtep IP address

Please consider marking this answer "correct" or "helpful" if you think your question have been answered correctly. Regards, Jeffrey Lingle
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