>> Hi all - horse will be down all Saturday. > > And horse is now back in service.
Following on from this... I've finally solved the problem which meant latency between horse and the firewall was anything from 0.1 ms to 5000 ms over a simple piece of crossover ethernet. Turns out that the freeBSD kernel on the firewall was the SMP flavour, which did not want to play nicely on a uniprocessor box (old compaq p3 500) Not sure why, but everything is back to normal.
