Hi,

There is no such thing as a fast UDP scan.
A UDP scan WILL take several hours even on a fast LAN as the target
operating system will limit its ICMP reply rate.
You can change this via /proc in linux.
You have other factors when running UDP scans over the Internet like
intermediate routers (read ISP mostly) and their UDP (oft dumb) filtering
policies.

You need to understand how datagrams are sent to each port being tested in a
UDP scan and the responses to them thereof.
The services running on the target machine will determine if you receive a
response, or not, as closed UDP ports should return an ICMP port unreachable
message.

Try: nmap -sU -T Polite -p- -P0 xxx.yyy.zzz.aaa for accurate results, but
don't hold your breath, they will take a long time.
The "-p-" switch is the same as -p 1-655535.

Also, running parallel scans will help, as long as they're not against the
same target.

Patience is key with UDP scans, where's the fire?
Read the extremely well laid out: http://insecure.org/nmap/nmap_doc.html

- S

-----Original Message-----
From: listbounce (at) securityfocus (dot) com [email concealed] [mailto:listbounce (at) securityfocus (dot) com [email concealed]] On
Behalf Of Attari Attari
Sent: Tuesday, August 21, 2007 12:03 PM
To: pen-test (at) securityfocus (dot) com [email concealed]
Subject: Fast UDP scan

Hi Group:

Is there a way to increase speed of UDP scan?

I'm running a full UDP scan since 3 days on 3 IP
addresses and it is still not complete.

I gave following command:

nmap -sU -p1-65535 -P0 xxx.yyy.zzz.aaa

One way I can think of is is running parallel nmap
scans by dividing ports like:

nmap -sU -p1-30000 -P0 xxx.yyy.zzz.aaa
nmap -sU -p30000-65535 -P0 xxx.yyy.zzz.aaa

Would appreciate some inputs on this.

Regards

Once upon a time there was 1 GB storage in your inbox. To know the
happy ending go to
http://help.yahoo.com/l/in/yahoo/mail/yahoomail/tools/tools-08.html

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