Nmap over pptp vpn

[ceefus]

Good Afternoon,

I'm having a bit of a problem running nmap over my VPN. We have 20 locations over 21 subnets.

Each is a class C (/24) network and they're all interfaced through routes on the RAS server and the local machines. I'm using kvpnc to access my vpn and the routes are setup correctly. I can remote manage every device on the network without an issue (phones, printers, pc's); and I can see them all with both ipscan and nbtscan.

All manual pings come back correctly, that is, if I ping a dead host it does not respond but a live host will respond.

When I run nmap: nmap -sP 10.xxx.xxx.x/24 it tells me every host is up; including .0 & .255.

My local interface is eth0 @ 192.xxx.xxx.xxx.
My VPN tunnel interface is ppp0 @ 10.xxx.xxx.xxx

Output from nmap --iflist looks correct

DEV (SHORT) IP/MASK TYPE UP MAC
lo (lo) 127.0.0.1/8 loopback up
eth0 (eth0) 192.xxx.xxx.xxx/24 ethernet up 00:16:76:6D:C5:94
ppp0 (ppp0) 10.xxx.xxx.xxx/32 point2point up

Any idea's?


Thanks!

[Archangel-Amael]

Nmap has plenty of documentation as well as a mailing list. It would be wise for you to ask there. They are the experts on it.

[VulcanX]

Only thing I can see there is that maybe you need to specify which interface to send the packets from.

nmap -sP -e ppp0 10.xxx.xxx.x/24

Try that and see the output, Im not too sure what the -sP does, could you tell me please? I tried to google a lil now and couldnt find it.

Hope this helps

[iproute]

-sP is ping only. I usually am only scanning one class C subnet. But I usually use 192.168.5.1-254 maybe try that range type notation rather than CIDR.