----- Original Message ----- From: "Priscilla Oppenheimer" To: Sent: 11 September 2002 6:45 pm Subject: RE: The Origin of Echos and Echo Replies [7:53148]
> To be absolutely sure I would want to use a serial protocol analyzer, but > alas, those are too expensive for the self-employed. But I'm 99% convinced > by the testing that I did. I'm wondering if there are any obstacles to using the following strategy to avoid the usually traumatic financial consequences associated with the serial protocol analyzer option: 1: apply strict acls permitting only the test traffic to the remote router's serial interface 2: clear all counters 3: generate traffic 4: review the interface statistics (something like show int s | i received|input) for evidence that the packets traversed the wire. > > Priscilla > > > I know > > this has been discussed in the past but I didn't find anything > > in the archives that exactly answers my question. > > > > It kinda makes sense that a local serial interface will > > encapsulate an echo packet that it receives and put it on the > > wire (it only knows how to encapsulate in one direction and > > de-encapsulate in the other). It makes sense that the > > distant-end router will return it, based on the destination IP > > in the packet. What I'm a little fuzzy on is why CCO says that > > the echo reply must also be sent accross the WAN and be > > returned by the distant end router. If it were the interface > > itself that had to generate the echo reply, I guess the same > > logic as before would apply. But does the router or the > > interface actually generate the reply? If it isn't the > > interface itself, it seems the router would simply generate a > > reply back towards the source IP (the ethernet interface - > > which is essentially itself). Is it required that an ICMP > > packet actually be given life on a hardware interface and thus > > the one-directional encapsulation issue comes back into play > > again? > > > > Or am I just really confused about it all? > > > > Thanks all, > > > > Scott Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=53196&t=53148 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
