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List:       nmap-dev
Subject:    Re[2]: Speeding up single ports scans over large networks
From:       Bo Cato <jcato73 () comcast ! net>
Date:       2003-09-19 5:49:04
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Not sure if this helps but I tried this as well but have different
results. I scanned a very distant class b with the same switches you
used. After over 7500 hosts were scanned with no trouble I ended the
scan. It took approximately 10 minutes so I averaged around 12 - 13 hosts
per second. I run iptables and did not disable any of my rules. I -j drop
just about everything. I did not receive any 'sendto in send_tcp...'
messages.

I'm running the newly built nmap 3.45 on the 2.4.18 linux kernel. My
processor is an old Pentium 166 MMX and I have 128 mb ram.

I hope this is somehow helpful information. It's quite late so I hope
I didn't mistype this too badly. :-)

-b


Hello testic,

Friday, September 19, 2003, 1:16:39 AM, you wrote:

t> Hi again,

t> I used the commandline of

t> nmap -PS80 -sS -p80 -oG [filename] -n -T4 [Netblock]

t> And it was rather quicker, much better, however Nmap SIGSEGV after scanning
t> 6630 hosts producing a core dump :\

t> I then used: nmap --resume [filename]
t> Nmap then reported that '--resume' was an unrecognized option, after a pause
t> of a few seconds it resumed anyway.

t> Also I get the occasional 'sendto in send_tcp_raw: sendto(4, packet, 40, 0,
t> <IP>, 16) => Operation not permitted' style message, I have previously
t> understood that this was due to IPTables and/or other firewall software
t> running on the scanning machine, with this in mind I had turned off IPTables
t> for the duration of this scan and Nmap is running as root, any ideas as to
t> why these messages appear?

t> Update: Another SIGSEGV after a total of 9616 hosts.

t> I shall defer from resuming this scan until pending further information.

t> -testic


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