Nmap Development: Re: nmap 3.50 Oddity on FreeBSD 4.9-RELEASE

[MadHat <madhat () unspecific com>]

On Mar 20, 2004, at 12:24 AM, eric wrote:
> Thinking that I'd get around the following problem, I switched my
> attack host from OpenBSD to FreeBSD. However, when using the
> following attack method...
>
> sudo nmap -sS -p '1-65535' -g 53 -oG foo.gnmap  -T 4 -iL foo.list
>
> I get the following..
>
> sendto in send_ip_raw: sendto(6, packet, 28, 0, 10.51.55.0, 16) =>
> Can't assign requested address
> Sleeping 15 seconds then retrying
OK, this may or may not be related to your issue, but I found it did 
help on my BSD scanning server.  In sysctl, there is a setting for 
net.inet.icmp.icmplim, the value I had was a positive int around 200, 
not sure the default.  If you set this to 0, this may help fix the 
issue.
If you have the log_in_vain enabled for TCP or ICMP, you might see 
messages in your syslog regarding bandwidth limitations (x/y pps).  
From the reading I have done, this should only effect incoming packets, 
but I seem to remember this was not the case.  The number is the number 
of packets per second allowed and according to the docs is ICMP or TCP 
RST packets.
Because you are doing a SYN scan, and not a full connect scan, it is 
possible this could be an issue because the scanning host should try 
and send RST packets when it sees the SYN/ACK and you will also see 
ICMP port unreachable or admin prohibited when appropriate.
I doubt if it could cause the error you are seeing, but it might help 
in scanning.
I have gotten that error before but not on a regular basis and I can 
never seem to reproduce it when I want to.

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