Sending packets through router

Hey guys, recently downloaded NmapNT, but having troubles using it.

I understand the cmd functions and syntax, but what I dont get is why the packets aren't getting through to the remote host. I read an earlier article on a similar subject, but I think my network driver is the cause.

How do I send packets from my router? I think my packets are being modified in accord with my router, which is screwing everything up. In fact, almost every prog that uses raw winsocks are reacting in the same way: with some error message of the sort.

Do I connect to my router via telnet? If so, with what service, since I really dont want (and dont know how) to use telnet properly.

Thanks

What kind of router?

Just out of curiousity, who's network are you attempting to scan?

Microsoft Broadband Networking Wireless Base Station

(MN-500)

Quote:

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Originally posted here by breakology
Just out of curiousity, who's network are you attempting to scan?

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Not yours.

What perked your curiosity? nmap is not used strictly for blackhat activities, I shouldn't have to disclose the purpose for which I am using it.

c'mon man, ive been here a year; I know my limits. :rolleyes:

Did I mention malicious? I was just curious, don't be so touchy.

I know that on most routers showtime you type in the IP of the router into the Address bar of Internet explorer. That takes you to a config page usually.

Now usually, if you install nmap on a windows computer you have to have Winpcap installed on your machine. Did you install those.

If not, they are available at.

http://winpcap.polito.it

Yep, WinPcap is installed (latest version).

I need to send packets from my router, so that they are not modified in any way. Any more suggestions?

What sort of connection do you have? Cable, DSL, Dial-up? Also what commands are you using while scanning?

WinPCAP has some issues with PPP/PPPoE (Dial-up/DSL) connections. Getting it to work can be iffy. I have two systems, both running XP Pro (same upgrades, patches, everything.. could pretty much be ghost images of each other). I have them both on DSL. On my desktop if i attempt to run nmap I'll get no response, or the computer will hang. On my laptop I was getting no response, until i changed my scan type from Syn Scan (-sS) to TCP Connect (-sT). I can run scans using TCP Connect, however I still get nothing with -sS. I can't explain why as I'm still working on that, but in the mean time this may be a work around for you.

Also your router should not be affecting the scan, it's a piece of networking technology, it has the same abilities to send as your computer does. However you could attempt to set-up the computer you are scanning from as a DMZ on your router. That should clear up that issue for you.

Showtime8000 ,

I dont think your problem is related to routing. Especially if your router is routing unicast packets without any problems, and you are not filering any ports...

Try scanning someone local (get another PC if you have one) on same LAN to eliminate configuration/application issue.

Cheers.


P.S
Showtime8000 , a router does not by default modify a packet in any way. It routes packets based on dst IP address period!!!!!!

As somebody else previously stated, try doing a full connect scan (-sT) instead of just using the SYN scan. I dont know what it is, but my windows box doesnt like it when a TCP connection isnt fully opened or left hanging in anyways.

Dont use fragmentation (You didnt say you have, but I figured I'd throw this in anyway) I dont know about everybody else, but Windows doesnt seem to deal well with fragmented packets, either receiving OR generating them.

Use the very verbose option (-vv) as this is a good way to see if its even getting the ICMP packets out on the wire. I really dont know why but sometimes it will ping the hosts, but wont initiate the scan. I've also noticed that if you turn off the DNS resolution it will sometimes hang, others it will drastically speed things up.

I have had some problems (and some solutions) with Nmap for Windows. Personally I think it is a buggy piece of ****, but there are ways to get around some of the issues I have found. If your looking for a good reliable scanner for windows I would reccomend IPTools. Hope this helps.

Jonesy

Try going into the router and look for packet sending and enable it

Quote:

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Originally posted here by Showtime8000
I need to send packets from my router, so that they are not modified in any way. Any more suggestions?

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I'm not sure to understand!
What do you mean by send packets from my router ?

Do u mean that your are generating frames with the src IPaddy of the router from an NT platform?
If this is the case nmap will never receive any probes return coze the router will legitimately understand that it is the owner of it and therefore won't forward it!

(Just a suggestion: You should use a sniffer such as ethercap to monitor exactly what's going out from your PC supporting nmap.)