blog Linux Ubuntu VMWare

Centos 7.6 Minimal Post Install Change

I’m working on a project at a customer location this week and this particular project required me to install Centos 7+.  Being an Ubuntu guy, I kicked and moaned for about 3 whole seconds and started the install.  It went as smooth as you’d expect, however, I was greeted with no network connectivity once Centos rebooted.  Mentally, I thought it was needing VMWare drivers or something but as it turns out, I just needed to enable the network interface.

vi /etc/sysconfig/network-scripts/ifcfg-<cardname>

Now change ONBOOT=No to ONBOOT=Yes

Then simply reboot and make sure you can get connected to the network.

Microsoft VMWare Windows

Server 2016 VM losing network connectivity on VMWare ESXi 6.5

I ran into an issue recently where servers that have been running for 6+ months with normal patching/rebooting, but without issue, all of a sudden started losing network connectivity.  The icon would pop up in the tray and the server was no longer reachable.  I still don’t know the underlying cause of the issue, but here’s what I figured out.

Thanks to this blog post, I was able to throw some commands at the box (network tuning stuff) and determine which specific command fixed the network access.

Here are the commands:
netsh int tcp set global chimney=Disabled
netsh int tcp set global autotuninglevel=normal
netsh int tcp set supplemental custom congestionprovider=none
netsh int tcp set global ecncapability=Disabled
netsh int ip set global taskoffload=disabled
netsh int tcp set global timestamps=Disabled
netsh int tcp set global RSS=Enable
netsh int tcp set global rsc=disabled

The supplemental custom command didn’t work for some reason, but the winner here was to enable RSS on the network interface.

Hope this helps.