Re: [LI] Duplicate packets

[Sharad Joshi <sharadj@xxxxxxxxxxxxxxxx>]

On Sun, 26 Dec 1999, Ramachandran Prakash wrote:

+ 64 bytes from 202.141.63.4: icmp_seq=0 ttl=255 time=2.6 ms
+ 64 bytes from 202.141.63.4: icmp_seq=0 ttl=254 time=2.8 ms (DUP!)
+ 64 bytes from 202.141.63.4: icmp_seq=0 ttl=255 time=3.0 ms (DUP!)
+ 64 bytes from 202.141.63.4: icmp_seq=0 ttl=254 time=3.2 ms (DUP!) 
+ 
+ u can see here that each of the packets is repeating itself about 4 times ..
+ this occurs when i ping from - to the machines with the  Ethernet controller:
+ Intel 82557 (rev 8). 
+ 
+ where as when i ping from my machine to others with some other ethernet
+ controller i get this message ping cyberspace.org
+ PING cyberspace.org (204.212.46.130) from 202.141.63.136 : 56(84) bytes of data.
+ 64 bytes from 204.212.46.130: icmp_seq=0 ttl=240 time=2048.0 ms
+ 64 bytes from 204.212.46.130: icmp_seq=0 ttl=239 time=2048.4 ms (DUP!)
+ 64 bytes from 204.212.46.130: icmp_seq=1 ttl=240 time=1408.3 ms
+ 64 bytes from 204.212.46.130: icmp_seq=1 ttl=239 time=1408.6 ms (DUP!) 
+ here it is occuring only once.. 
+ 

To quote from the ping(8) manual,

  DUPLICATE AND DAMAGED PACKETS
     Ping will report duplicate and damaged packets.  Duplicate packets
     should never occur, and seem to be caused by inappropriate link-level
     retransmissions.   Duplicates may occur in many situations and are
     rarely (if ever)  a good sign, although the presence of low levels of
     duplicates may not always be cause for alarm.

So, this is the case of erronous link layer xmission. Is "your" card ok?

Sharad.

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