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New Member

3550 switch dropping connection

Has anyone seen this before....I have a customer site that connects to us. They have no security or anything they are wide open and my side has a 515E pix firewall with a NATed IP address that this user can connect to. The problem is is that I can send constaint pings to this guy with no issues but when he tries to ping me he can at times and at times he cannot ping me. I doubled check my rules on the firewall to ensure it isn't me. As far as the connection goes nothing is blocking he is wide open on the NATed IP he connect to. I'm thinking it is a routing issue on his side but then I find out that at times his whole office drops connection could it be that the 3550 switch is over taxed and drops the connection? It also doesn't help that this guy will not work with me so it is kinda hard to see what his network is like.

VIP Purple

Re: 3550 switch dropping connection


it could very well be that the reason is the 3550. There have been a couple of posts here lately dealing with problems in getting a PING to a switch, and apparently, at least according to Cisco, switches are architecturally optimized for Layer 2 traffic and not for e.g. ICMP traffic, so it could happen that PINGs are dropped or are otherwise slow.

That said, since the customer´s connection drops alltogether, there might be something else in the path. You could use a utility such as PingPlotter (you can download it at that will show you all the hops and corresponding delays between a source and destination. That might at least give you an idea of where the ´bottleneck´ might be...



New Member

Re: 3550 switch dropping connection

Thank you for the response, I believe it is the router causing the problems. I was able to sneak a peak in their datacenter and found out that the router isn't a 3550 at all it is one of those wireless/mobile routers a 3250 that is supporting their main site. But anyways going to go ahead with your suggestion and use the ping plotter to find out where the bottleneck is. Let you know what the outcome is.

Thank you


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