Okay so this one's a doozy. I'm pretty sure it's an OS X issue rather than a network system issue.
We have 2 offices, on two different IP ranges eg. 10.1.1.X and 10.1.2.X
We recently had a slew of problems in the remote office on the 10.1.2.X range. We've now got DHCP coming from our router/firewall and all seemed fine, until we started to play.
For ease of tracking we wanted to do DHCP with Manual Address, so we can specify each machine an IP which makes it easier for us working remotely. However as soon as this was applied they picked up a different subnet mask.
When on full DHCP they were assigned an IP and a subnet mask of 255.255.255.0 which is what we normally use.
However as soon as I set the IP manually it switches it over to 255.0.0.0
As soon as I go full manual, or full DHCP it works fine, it just seems to be with this manual IP, DHCP set up.
Has anyone encountered this before and how did you fix it?
I've attempted googling but I just come across a bunch of incorrect router settings posts. I've triple checked and they're correct, as sort of proven by the fact they work on full DHCP.