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Wireshark-users: Re: [Wireshark-users] Retransmissions inconsstent btw. wireshark and netstat

From: Sake Blok <sake@xxxxxxxxxx>
Date: Sun, 17 Feb 2008 22:01:30 +0100
On Sun, Feb 17, 2008 at 11:17:40AM -0800, Jock Purnell wrote:
> Thanks for the input.  I know we've tried changing the duplex 
> and speed settings for the NIC's, and it doesn't seem to make 
> any difference.   I'm going to try again, though, in a more 
> controlled environment.

Setting duplex and speed only works when the PC is connected
to a switch and not to a hub. Please note that when you are using
a switch, then setting the PC's NIC to fixed values also means
setting the switchport to fixed values. Otherwise you are very
likely to get a duplex mismatch between the switchport and the
NIC.

> To answer the question about the statistics.   It's under the 
> "Statistics for IPv4".
> Segments transmitted goes up by about 150, and segments 
> retransmitted goes up by about 1,000.  By my calculation, 
> it should take a bit more than 1,050 segments to send the 1.5Meg file.

That does strike to me like a little odd. I just ftp'd a file of 
493kB and my "Segments Sent" went up from 287721 to 288171. Which 
sounds about right, considering there is also other traffic on this
PC. I saw "Segments Retransmitted" increase by only 1.

What do the "IPv4 Statistics" tell you when you look at them
just before and after the FTP upload? By how much does
"Output Requests" increase?


Cheers,
    Sake