On 23/03/09 01:15 PM, Zhenghui.Xie at Sun.COM wrote: > I found that Foundry was using this approach for udp probe: > > send some garbage data. If ICMP port unreachable is detected, then udp > health check is considered fail. If no reply from server, it consider > the port is alive and received the garbage data, and udp health check > is considered succeed. > > does this sound a qualified approach for udp? > > comments from Kacheong: > > You and I have talked about this using a zero length UDP > packet, instead of some garbage data. The use of garbage > data can be a problem to some apps. But for some stack, > zero length UDP packet may be dropped. If you are going > to do this probe, there should be a tunable to specify > the length of the UDP packet. > > And if this probe is used, I guess it should be coupled > with at least a ping probe. No reply can just mean that > the server is completely dead. So only if ping probe is > OK, no response to the UDP probe may make sense. > > I think this should be brought up in the ilb-dev list. > > Any other suggestions?
Look at what nmap does. Darren
