Ping/etc. Problems -- MIDRANGE-L

When you get a reply after the wait interval (default 1 second) the 400 
will identify them as (Duplicate) as in this example:

ping someplace
Verifying connection to host system someplace at address 999.999.0.240.  
No response from host within 1 seconds for connection verification 1. 
No response from host within 1 seconds for connection verification 1.
No response from host within 1 seconds for connection verification 2.
PING reply 1 from 999.999.0.240 took 2142 ms. 256 bytes. TTL 236. 
  (Duplicate) 
PING reply 2 from 999.999.0.240 took 2057 ms. 256 bytes. TTL 236. 
  (Duplicate) 
No response from host within 1 seconds for connection verification 3.
PING reply 3 from 999.999.0.240 took 1905 ms. 256 bytes. TTL 236. 
  (Duplicate) 
No response from host within 1 seconds for connection verification 4.
No response from host within 1 seconds for connection verification 5.
Connection verification statistics: 0 of 5 successful (0 %). 

... Neil





thomas@inorbit.com
Sent by: owner-midrange-l@midrange.com
2001/07/13 17:04
Please respond to MIDRANGE-L

 
        To:     MIDRANGE-L@midrange.com
        cc: 
        Subject:        Re: MIDRANGE-L Digest V4 #735


Jim:

This doesn't sound quite right, though I'm no expert at this. The advice 
about increasing the time interval is good; AFAIK that should be one of 
the first steps in resolving ping issues.

But your explanation of what you were seeing seems incomplete. I would 
expect that ping 2 would not respond to the pong from ping 1 or, by pings 
3 and 4, you'd start getting notification of duplicate ping packets (if 
ping 3 showed timeout, then both pong 2 and 3 should arrive during ping 4) 
or each ping after the first would simply receive the reply from the 
previous ping (ping 1 times out, ping 2 sees response from ping 1, ping 3 
sees response from ping 2, etc.)

Although I've seen timing issues as you describe, I've never seen the 
behavior that you saw. I had somewhere gotten the understanding that each 
ping packet had a unique (sequential?) identifier to ensure that ping 2 
would not respond to the pong from ping 1. But your experience calls that 
into question. How did you determine what was happening in your case?

Tom Liotta

On Thu, 12 July 2001, Jim Langston wrote:

> 
> One time I was having trouble connecting to another server on our WAN, 
and
> Pings were showing exactly 50% drops.  That is, every other ping was 
timing out.
> 
> So, what I did what increase the time to wait for the response on the 
Ping command
> to like 10 seconds, and I actually saw that I was receiving every single 
ping, just
> very slowly.
> 
> So why did I initially see every other ping?  The timing.  Pings wait 1 
second as
> the default before timing out.  So, it would send a ping, wait one 
second for a
> response, state it timed out, send the second ping, wait... and receive 
the 
> response from the first ping!  It would report this as the second ping, 
then it
> would send the third ping, time out, send the 4th ping, and receive the 
response
> to the third ping... 

-- 
Tom Liotta
The PowerTech Group, Inc.
19426 68th Avenue South
Kent, WA 98032
Phone  253-872-7788
Fax  253-872-7904
http://www.400Security.com




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