Today I had a strange problem with a new Sophos RED15 device. The customer told me that they have many interrupts through a transparent RED device. There were these lines in the log:
2015:09:22-11:11:34 utm-1 red2ctl: Overflow happened on reds1:0
2015:09:22-11:11:34 utm-1 red2ctl: Missing keepalive from reds1:0, disabling peer 80.135.xx.xx
I controlled the configuration and saw the suspected error:
the device is running in transparent mode between a PC and the local network. The uplink address and the LAN address are the same! In this case you will get always an IP-address-conflict. Changing the internal address to 192.168.178.11 and restarting the RED brought the solution!