I recently ran into an issue with vSphere Replication that involved network connectivity (probably a future post), and I quickly realized that VMware network test commands are not consistent across all their products, so this could be confusing for many people. I’ll update this post later as I get the commands for other products, but this may help someone looking for how to do VMware network testing and troubleshooting.
ESXi has two helpful commands. For basic connectivity tests, vmkping is awesome because it’s simple to use and to specify which kernel port group you want to test. Sure, you could use ping, but you can’t specify which vmk interface with it.
To ping 192.168.1.1 with your Management Port group, assuming it’s default, so it’s using vmk0, it’s simply:
vmkping 192.168.1.1 -I vmk0
Another good use is validating jumbo frames, as you can specify the packet size as well and disable packet fragmentation. To conduct the same test with a packet size of 9000 and ensure the packet doesn’t get fragmented:
vmkping 192.168.1.1 -I vmk0 -s 9000 -d
For testing specific port connectivity, ESXi does support the netcat, aka nc command. To test port 80 on destination 192.168.1.1:
nc -z 192.168.1.1 80
You can specify UDP mode using -u as well. Note that at least in my experience -s <source IP> does NOT work, so I don’t believe it’s possible to specifically direct netcat through a specific vmkernel port. When I tried it for example forcing it through an IP that shouldn’t work, connectivity was still made when it shouldn’t have.
Any VMware Product Running on Windows 2012 or Higher (vCenter, SRM)
Everybody knows ping. I’m not gonna go over that. But did you know that PowerShell has a ping cmdlet? This is useful for documentation of results, using export-csv, and scripting lots of ping tests.
To ping 192.168.1.1:
Another handy trick is you can remotely have multiple Windows machines ping the same computer and/or specify multiple targets. For example, if I want server1, server2, to ping 192.168.1.1 and 192.168.1.2:
test-connection -Source Server1,Server2 -ComputerName server3,server4
PowerShell also has cmdlets to test network port connectivity as well. To test if the local machine can connect to 192.168.1.1 on TCP port 80:
test-netconnection -computername 192.168.1.1 -InformationLevel detailed -port 80
Unfortunately, there isn’t a handy -source parameter, but you could use PowerShell remoting to run this command on multiple remote computers, too.
VMware vCenter Server Appliance
For pinging, there’s the ping command. That’s easy enough.
If you try to use netcat for port testing, it isn’t there by default. You have to run the following to temporarily install it on version 6:
Rebooting the VCSA removes it.
You can also use curl if that’s something you’d rather not do:
curl -v telnet://192.168.1.1:80
vSphere Replication Appliance
For pinging, there’s the ping command. No surprises.
For network port testing, again, netcat isn’t installed, nor is there a supported way to install it to my knowledge. Instead, use the curl command:
curl -v telnet://192.168.1.1:80
Keep checking back, as I add more.