[tech] DHCP Issues Fixed

[David Adam]

On Sun, 9 Dec 2012, John Hodge wrote:
> The DHCP issues that have been plauging the UCC network have now been fixed.
> The problem was bitumen was treating all network ports as possible links to
> other switches and attemting a STP handshake on them and hence wouldn't pass
> traffic for a good 30s or so. This meant that when a link came back up (either
> by a reboot or the cable being dislodged) no traffic would flow, and hence the
> DHCP requests weren't seen by murasoi.
> 
> Portfast has now been enabled by default on all non-trunk ports, save for a
> few that had issues with it (heathred being one, which is why it went down
> earlier this evening)
> 
> tl;dr - Network works again, netboot and wireless should just connect quite
> nicely (and now works better than Unifi again)

We should probably enable Rapid PVST+, which is what we used to run on 
Coconut until Bitumen took over. I don't really want to do this without 
having a serial connection to the switch Just In Case, but perhaps someone 
who is in the machine room could give it a crack.

(It's really as simple as `spanning-tree mode rapid-pvst`.)

I'd be surprised if this fixed perceived issues with the wireless, though; 
connections from wireless clients won't make the switchport on Bitumen 
toggle spanning tree state.

However I have just realised that the wireless bridge (the bridge part of 
which is a Linux software bridge on Coromandel) does run STP, and this is 
probably messing up DHCP, so I've turned it off.

[DAA]
zanchey@