A quick piece of advice for anyone thinking of purchasing a Netgear GS748T – don’t even think about it until they’ve brought out newer firmware than 1.0.3_10.

We’ve been using Netgears as our access and distribution layer switches for years now, and never had a problem with them. Reliable, easy to use (especially the old-style telnet interface), solid. Until now.

I came across a bug in them at the weekend which is, umm, interesting. If you put in a moderately complicated VLAN configuration, then most of the way through the process the web interface gives the error “Entry not found”. After that happens, the PVID table (that is, the table which says which vlan to put each port’s incoming untagged packets on) suddenly goes from being sensible to mostly containing “0″, with some randomly large numbers like 61728347 and -2184574 (ish) thrown in on some ports for good measure. If the switch was actually in use, this would of course screw up all of your network.

After replacing all of the table entries with the right numbers, port 48 resolutely stays with a PVID of 0 (which is invalid – VLAN IDs must be 1-4096). Even after a factory reset and downgrading/upgrading the firmware, port 48 stays at 0, which effectively makes it unusable. The switch is now permanently broken (unless a future firmware update can somehow fix it).

Netgear support tell me they’re “aware of the problem”. That’s good, at least I don’t have to prove it to them. But not good enough for me right now, because I need to upgrade our network pretty urgently (more on that in a future post). I’m hoping to be able to send these switches back, get some 3com 3CBLSG48 switches, and do the upgrade this weekend instead.