I have a network with 4 daisy chained Catalyst 2950 and 2960 switches that has been working for years. I built a new network with a different ISP with the same internal address space. I thought that I could connect the two networks together, then move my users over to start using the new ISP and then disconnect the old ISP. When I connect a switch from the old network to a switch on the new network I start having problems. Traffic from the new network going to the old is sporadic and then eventually (10 to 15 minutes) servers on the old network can't see each other. I have STP turned off because I don't have any redundant loops. Should I be able to do this and if so what would cause this result?