Thanx, I though it would be something like that. Another question, how long must I keep a GUID? I can imaging that a ping (and it's pongs) should be long out of the network after 1 minute. However, a queryhit not, since it can receive a push, which could be sent a few mintes later, or is it a good idea to always keep track of servent id's, and not remove them after some time?