Help understanding a trace of an nmap scan

From: Richard Moore (rich@westpoint.ltd.uk)
Date: Mon Sep 06 2004 - 10:11:07 EDT


I wonder if anyone can help me make sense of this packet trace. It shows
nmap running a connect scan against port 13 of a host. The part I don't
understand is why there are 3 RST packets sent to the target machine?

If it helps anyone the target host is a Debian box running 2.4.26 Linux
kernel and the source machine was a RedHat box running 2.4.7-10. The
version of nmap used is 3.48.

Cheers

Rich.

-- 
Richard Moore, Principle Software Engineer,
Westpoint Ltd,
Albion Wharf, 19 Albion Street, Manchester, M1 5LN, England
Tel: +44 161 237 1028
Fax: +44 161 237 1031

14:16:23.098150 host.name.deleted > other.host.name: icmp: echo request
14:16:23.108150 host.name.deleted.45639 > other.host.name.http: . ack 901588830 win 1024
14:16:23.108150 other.host.name > host.name.deleted: icmp: echo reply
14:16:23.108150 other.host.name.http > host.name.deleted.45639: R 901588830:901588830(0) win 0 (DF)
14:16:23.428150 host.name.deleted.1073 > other.host.name.daytime: S 2950063922:2950063922(0) win 5840 <mss 1460,sackOK,timestamp 51097216 0,nop,wscale 0> (DF)
14:16:23.438150 other.host.name.daytime > host.name.deleted.1073: S 1866105343:1866105343(0) ack 2950063923 win 5792 <mss 1460,sackOK,timestamp 138541011 51097216,nop,wscale 0> (DF)
14:16:23.438150 host.name.deleted.1073 > other.host.name.daytime: . ack 1 win 5840 <nop,nop,timestamp 51097217 138541011> (DF)
14:16:23.438150 host.name.deleted.1073 > other.host.name.daytime: R 1:1(0) ack 1 win 5840 <nop,nop,timestamp 51097217 138541011> (DF)
Interesting ports on other.host.name (194.153.168.235):
14:16:23.448150 other.host.name.daytime > host.name.deleted.1073: P 1:27(26) ack 1 win 5792 <nop,nop,timestamp 138541012 51097217> (DF)
14:16:23.448150 host.name.deleted.1073 > other.host.name.daytime: R 2950063923:2950063923(0) win 0 (DF)
14:16:23.448150 other.host.name.daytime > host.name.deleted.1073: F 27:27(0) ack 1 win 5792 <nop,nop,timestamp 138541012 51097217> (DF)
14:16:23.448150 host.name.deleted.1073 > other.host.name.daytime: R 2950063923:2950063923(0) win 0 (DF)


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