["Tom C. Barker" <TomBarker@xxxxxxxxxxxx>]

Thanks Wrolf,

What I found was that line 5 was a premature close. 4 was a dropped 
packet (at the ip level) and my application erroneously closed the 
connection. Notice that line 10 is the proper response to a received 
request. My well-behaved application now simply waits for ( in this case ) 
another request which checksums properly and is passed up the stack.

2026 > http [SYN] Seq=3726085043 Ack=0 Win=65535 Len=0
http > 2026 [SYN, ACK] Seq=7151 Ack=3726085044 Win=2048 Len=0
2026 > http [ACK] Seq=3726085044 Ack=7152 Win=65535 Len=0
GET /portCh2.gif HTTP/1.1
GET /portCh2.gif HTTP/1.1
http > 2026 [ACK] Seq=7152 Ack=3726085312 Win=1780 Len=0
Continuation
http > 2026 [FIN, ACK] Seq=7358 Ack=3726085312 Win=1780 Len=0
2026 > http [ACK] Seq=3726085312 Ack=7359 Win=65329 Len=0
2026 > http [FIN, ACK] Seq=3726085312 Ack=7359 Win=65329 Len=0
http > 2026 [ACK] Seq=7359 Ack=3726085313 Win=1779 Len=0

Thanks again,
Tom


-----Original Message-----
From: wrolf.courtney@xxxxxxxxxxxxxxx
[mailto:wrolf.courtney@xxxxxxxxxxxxxxx]
Sent: Tuesday, January 13, 2004 6:47 AM
To: Tom C. Barker
Cc: 'ethereal-users@xxxxxxxxxxxx'
Subject: Re: [Ethereal-users] Advice on an HTTP request






1  C TCP  2394 > http [SYN] Seq=1716877397 Ack=0 Win=65535 Len=0
2  S TCP  http > 2394 [SYN, ACK] Seq=9296 Ack=1716877398 Win=2048 Len=0
3  C TCP  2394 > http [ACK] Seq=1716877398 Ack=9297 Win=65535 Len=0

Your client sent Seq=...97 in packet 1, but  Seq=...98 in packet 3, without
sending another byte.

The server ignores the data sent later, and is still waiting for the
missing byte.  Eventually it closes thet connection, when the client won't
send up the missing byte.

Wrolf Courtney
Donovan Data Systems, Inc.
(212) 633-5470



 

                      "Tom C. Barker"

                      <TomBarker@xxxxxxxxxxxx>         To:
"'ethereal-users@xxxxxxxxxxxx'" <ethereal-users@xxxxxxxxxxxx>

                      Sent by:                         cc:

                      ethereal-users-bounces@e         Subject:
[Ethereal-users] Advice on an HTTP request

                      thereal.com

 

 

                      01/12/2004 06:44 PM

 




Hello,

Following is an Ethereal dump of an HTTP request for a graphic. The browser

requesting the file is IE 6.01, but I have seen this on Netscape also.
In line 4, "C HTTP GET /titleMIH.gif HTTP/1.1" was corrupted at reception
and did not pass the checksum routine (ok, fine). Next the connection
closes.
Curiously, the client asks for the file again, without ever setting up the
connection (so it seems to me). The server then ACKS, I think (8), and then

the conversation ends.

Could someone offer me an explanation as to what might be happening here
and if there is any necessary tweaking that might go on in the server code
to recover? Is this conversation proper in light of the fact the the second
request may have been dropped at the hardware also? Any comments to the
appropriateness of how the browser is acting in this conversation is
certainly
welcome.

Thanks,
Tom Barker


1  C TCP  2394 > http [SYN] Seq=1716877397 Ack=0 Win=65535 Len=0
2  S TCP  http > 2394 [SYN, ACK] Seq=9296 Ack=1716877398 Win=2048 Len=0
3  C TCP  2394 > http [ACK] Seq=1716877398 Ack=9297 Win=65535 Len=0
4  C HTTP GET /titleMIH.gif HTTP/1.1
5  S TCP  http > 2394 [FIN, ACK] Seq=9297 Ack=1716877398 Win=2048 Len=0
6  C TCP  2394 > http [ACK] Seq=1716877667 Ack=9298 Win=65535 Len=0
7  C TCP  2394 > http [FIN, ACK] Seq=1716877667 Ack=9298 Win=65535 Len=0
8  S TCP  http > 2394 [ACK] Seq=9298 Ack=1716877398 Win=2048 Len=0
9  C HTTP GET /titleMIH.gif HTTP/1.1
10 S TCP  http > 2394 [ACK] Seq=9298 Ack=1716877667 Win=2048 Len=0
11 C TCP  2394 > http [FIN, ACK] Seq=1716877667 Ack=9298 Win=65535 Len=0
12 S TCP  http > 2394 [RST, ACK] Seq=9299 Ack=1716877668 Win=2048 Len=0

_______________________________________________
Ethereal-users mailing list
Ethereal-users@xxxxxxxxxxxx
http://www.ethereal.com/mailman/listinfo/ethereal-users


_______________________________________________
Ethereal-users mailing list
Ethereal-users@xxxxxxxxxxxx
http://www.ethereal.com/mailman/listinfo/ethereal-users