pfSense

We have a client with pfSense 2.7.2, which was just upgraded from a very old version. OpenVPN is used for Windows 11 clients. Most worked fine, but some would have connection failures with a message such as "Notified TAP-Windows driver to set a DHCP IP/netmask of 0.0.0.2/255.255.255.252 on interface".

I was a little baffled, thinking it was something on the client causing this, but it was actually the server pushing this using a "ifconfig 0.0.0.2 0.0.0.1" command.

I happened to see that, in the client specific override for some users, a space was added to the end of the /30 network specified in the IPv4 Tunnel Network field.

Removing the trailing space fixed the issue, crazy enough. The ifconfig command had the respective /30 IPs for the client and server and all is well.

I would suggest trimming whitespace off the beginning and end of the fields, or taking a look at the configuration upgrade which may have an issue. Note that I'm not 100% sure if we accidentally had a space on the end of this subnet prior to the upgrade or not - but OpenVPN worked fine prior to the upgrade.

Just wanted to provide some search keywords for others who may have seen this issue and weren't sure what was causing it.