nmap not scanning networks?
Chuck Swiger
cswiger at mac.com
Wed Jun 16 18:39:20 GMT 2004
Alex Povolotsky wrote:
> Attempt to scan a network with any method except plain ping results in an error:
>
> truss nmap -sT -p 21 '172.19.17.*'
I can confirm the problem, anyway, although I'm not sure it's germane to
freebsd-security. :-)
> [...]
> sendto(0x4,0x8094200,0,0x0,{ AF_INET 172.19.17.0:0 },0x10) ERR#49 'Can't assign
> requested address'
> [...]
>
> What's strange that man on send(2) doesn't state that EADDRNOTAVAIL can ever be returned from sendto().
nmap interprets the wildcard character in a network address to include the
all-zeros "base network address" and the all-ones "network broadcast address".
I seem to recall that some systems won't let you send traffic to the
all-zeros address which might explain the EADDRNOTAVAIL, although my
explanation is not entirely satisfactory as there are still problems:
Consider trying "nmap -sT -p 21 '172.19.17.1-255'", only it results in similar
behavior:
# nmap -sT -p 21 '10.1.1.1-10'
Starting nmap 3.50 ( http://www.insecure.org/nmap/ ) at 2004-06-16 14:29 EDT
sendto in send_ip_raw: sendto(4, packet, 28, 0, 10.1.1.1, 16) => Can't assign
requested address
Sleeping 15 seconds then retrying
--
-Chuck
PS: I would suggest CC'ing the port maintainer of nmap about this and maybe
moving the discussion to freebsd-ports...?
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