Date: Fri, 21 Mar 2003 04:02:53 +0200 From: Giorgos Keramidas <keramida@ceid.upatras.gr> To: John Fitzgibbon <fitz@jfitz.com> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Repeated ACKs - possible DoS? Message-ID: <20030321020253.GA3174@gothmog.gr> In-Reply-To: <200303201715.32293.fitz@jfitz.com> References: <200303201408.53238.fitz@jfitz.com> <20030321004312.GA1964@gothmog.gr> <200303201715.32293.fitz@jfitz.com>
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On 2003-03-20 17:15, John Fitzgibbon <fitz@jfitz.com> wrote: >On Thursday 20 March 2003 04:43 pm, Giorgos Keramidas wrote: >>> X is remote. Y is server, (FreeBSD 4.7-STABLE, built 2003/01/06) >>> >>> tcpdump shows 2 remote connections repeatedly sending "ack 1": >>> >>> 09:16:10.236812 X.64670 > Y.http: . ack 1 win 32589 >>> 09:16:10.236879 Y.http > X.64670: . ack 489 win 58400 (DF) >> >> Hmmm, is this repeatable? Can you try to grab the output of the >> following command in a log file while it happens? >> >> # tcpdump -n -v -s 128 -XX port 80 > > I haven't seen this behavior before, and I don't know how to recreate it :( Damn :( If this is a bug that you've hit upon, please note that command and run it if it ever happens to appear again. The log file is going to be large, but I'll help a lot to have it around when trying to find out what happens. - Giorgos To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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