We are using a 2511 (IOS 11.1) attached to a bank of modems to provide dialout support on our network by using reverse telnet to rotary port 7001. Occasionally individual router ports seem to lock DTR low with the result we can no longer dial from that port even though we can attach to it. Resetting the modem has no effect, nor does 'clear line' or 'clear int'. Resetting the entire router does in fact clear the problem. Does anybody have any ideas what causes this problem and how to prevent it?
