Quick Take: Syslog Stops Working after Upgrade to ESXi 5.0 Update 1

March 24, 2012

If you’ve recently upgraded your ESXi from 5.0 build 456551 and were logging to syslog, it’s possible that your events are no longer being received by your syslog server. It seems that there was a “feature” in ESXi 5.0 build 456551 that allowed syslog to escape the ESXi firewall regardless of the firewall setting. This could be especially problematic if your upgraded from ESXi 4.x where there was no firewall configuration needed for syslog traffic.

VMware notes that syslog traffic was not affected by the ESXi firewall in v5 build 456551. See KB2003322 for details.

However, in ESXi 5.0 Update 1, the firewall rules definitely applies and if you were “grandfathered-in” during the upgrade to build 456551: check your syslog for your ESXi 5 servers. If your no longer getting syslog entries, either set the policy in the host’s Configuration->Security Profile->Properties… control panel:

Enabling syslog traffic in the ESXi firewall within the vSphere Client interface.


Or use ESXCLI to do the work (especially with multiple hosts):

esxcli network firewall ruleset set –ruleset-id=syslog –enable=true

esxcli network firewall refresh

That will take care of the “absent” syslog entries.

SOLORI’s Take: Gotcha! As ESXi becomes more like ESX in terms of provisioning, old-school ESXiers (like me) need to make sure they’re up-to-speed on the latest changes in ESXi. Ashamed to admit it, but this exact scenario got me in my home lab… Until I stumbled onto KB2003322 I didn’t think to go back and check the ESXi firewall settings – after all, it was previously working 😉

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