Try turning off fast switching. Several years ago with early 12.0 code a similar problem existed with 2600s. The first ping would succeed because it was process switched. All subsequent pings would fail. Wait five minutes for the cache to clear and again the first ping would work. The "quick and dirty" fix was to disable fast switching. The real fix was to update IOS. The problem that you are describing seems different from the above - but maybe it's a starting point. Try using "sh int stat" and "sh int switching" and other show commands to watch for traffic.
> -----Original Message----- > From: Jenny McLeod [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, July 31, 2002 4:16 AM > To: [EMAIL PROTECTED] > Subject: Strange ping failures [7:50249] > > > Hi all, > I have just been battling a rather odd routing(?) problem. > > I have a 2621XM router, which has an ethernet segment > attached. This router > is connected to an AS5300 via a modem connected to the aux > port. The AS5300 > has other connections. Both routers have loopback interfaces > configured. > > Setup... > > Fa0/0--RTA--Aux--modem----AS5300--Fa0--lots of other stuff > > Routing is basically via static routes, because this is actually the > failover connection - RTA also has an ISDN connection via a > BRI interface > that, at the time of the problem, was (deliberately) down. > > Problem is, that I can ping from the AS5300 to the loopback > of RTA, or even > to the FA0/0 ip address, but I can't (usually) ping to any > hosts on the > Fa0/0 subnet. Nor can I ping from a PC on the RTA Fa0/0 > subnet to the AS5300. > > Weird thing? If I clear the IP routes on RTA, the next ping > (or two, on one > occasion) works. Then they start failing again. The pings > that work have > reasonably short response times, and even if I extend the > timeouts on the > failing pings to 20 seconds they don't work, so I don't think > it's a timeout > problem. > > I think I've seen this or read about this somewhere - it's > niggling at my > brain. But I can't work out what the heck is going on, and > my brain is now > fried. Any hints?? > > (If you're really interested in the ip addressing, I'll post it, but > according to the routing tables there is a path all the way > there and all > the way back). > > JMcL Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=50268&t=50249 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
