nmap on FreeBSD 7.0-RELEASE
Dave Edwards
dave.edwards at adelaide.on.net
Thu Nov 27 04:13:20 PST 2008
Hi,
I'm having some problems with nmap over the tun device. I connect to
the net using ppp and pppoe (adsl) which creates the "tun0" device. My
default route goes out that way.
Using nmap to try to map an external host:
-------------------------
# nmap -vvv -e tun0 -sS -p80,443 1.2.3.4
Starting Nmap 4.76 ( http://nmap.org ) at 2008-11-27 22:05 CST
WARNING: Unable to find appropriate interface for system route to 1.2.3.4
nexthost: failed to determine route to 1.2.3.4
QUITTING!
--------------------------
This only seems to occur when running nmap as root. As a normal user
(using the "connect" scan option) it seems to work ok, but you can only
run a SYN scan (or force a specific source port) as root. I think this
means that the problem may be related to using a raw socket..
I have the same problem with nmapping over a VPN tunnel as well (another
tun device) so I don't think it's the configuration of the ppp session.
As root, nmap finds the following interface list (note the missing
default route)
--------------------------
$ nmap --iflist
Starting Nmap 4.76 ( http://nmap.org ) at 2008-11-27 22:00 CST
************************INTERFACES************************
DEV (SHORT) IP/MASK TYPE UP MAC
rl0 (rl0) x.x.x.x ethernet up 00:00:E8:7A:EE:1C
re0 (re0) x.x.x.x ethernet up 00:E0:4C:50:19:8F
lo0 (lo0) 127.0.0.1/8 loopback up
tun0 (tun0) x.x.x.x/32 point2point up
WARNING: Unable to find appropriate interface for system route to
203.16.215.186
**************************ROUTES**************************
DST/MASK DEV GATEWAY
127.0.0.1/32 lo0 127.0.0.1
203.16.215.186/32 tun0 x.x.x.x
--------------------------
I've tried creating a host route for the nmap target instead of relying
on the default route and I've tried three other versions of nmap. As an
aside (or maybe a hint) when compiling nmap from source, there are a
number of warnings like:
------------------------
checking net/route.h presence... yes
configure: WARNING: net/route.h: present but cannot be compiled
configure: WARNING: net/route.h: check for missing prerequisite headers?
configure: WARNING: net/route.h: see the Autoconf documentation
configure: WARNING: net/route.h: section "Present But Cannot Be
Compiled"
configure: WARNING: net/route.h: proceeding with the preprocessor's result
configure: WARNING: net/route.h: in the future, the compiler will take
precedence
checking for net/route.h... yes
-------------------------
Google has let me down this time. There are a few comments about nmap
and FreeBSD but nothing that seems helpful and they are mostly fairly old.
Anyone got a clue for me?
davo
More information about the freebsd-net
mailing list