Nmap Development mailing list archives
Slow name-resolution of very large target list
From: Brandon Enright <bmenrigh () ucsd edu>
Date: Thu, 22 May 2008 07:16:31 +0000
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 All, I have a very large list (millions) of machines by name that I want to scan on a port using -iL. I've done this before with millions of IP addresses and had no trouble but as names the targets are resolving extremely slowly. Here is the command I'm using: nmap -iL host-list.txt -n -v -d -T5 -P0 --randomize-hosts -p <port> -sV -oA host-scan And here is a short excerpt of the host list: historycy.pl historydata.com historyday.crf-usa.org historydoc.edu.ru historyexam.hit.bg historyforkids.utah.gov historyfromthesea.net historyhunters.coolasmustard.com historyhuntersinternational.org historyillinois.org I've had the scan going for ~16 hours and only 40,000 hosts have been scanned. It appears as though 99% of the time is spent resolving target names. I've tried the scan from another network that has access to many very fast local DNS servers and have specified them with --dns-servers but that didn't seem to make any noticeable difference. I tried adjusting these parameters in nmap_dns.cc: #define CAPACITY_MIN 10 #define CAPACITY_MAX 200 #define CAPACITY_UP_STEP 2 but they didn't seem to have any noticeable effect either. Does anyone have any ideas for how I can go about troubleshooting this or speeding up name resolution? Brandon -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU/Linux) iEYEARECAAYFAkg1Hc8ACgkQqaGPzAsl94JZxwCgi+GLHW61BqjPWow7fC8GqEsX j1kAnj8+mDHmVmvbvckCjKCJQpJxxO2C =njXv -----END PGP SIGNATURE----- _______________________________________________ Sent through the nmap-dev mailing list http://cgi.insecure.org/mailman/listinfo/nmap-dev Archived at http://SecLists.Org
Current thread:
- Slow name-resolution of very large target list Brandon Enright (May 22)
- Re: Slow name-resolution of very large target list Fyodor (May 22)
- Re: Slow name-resolution of very large target list Brandon Enright (May 22)
- Re: Slow name-resolution of very large target list Fyodor (May 22)
- Re: Slow name-resolution of very large target list doug (May 22)
- Re: Slow name-resolution of very large target list Brandon Enright (May 22)
- Re: Slow name-resolution of very large target list doug (May 24)
- Re: Slow name-resolution of very large target list Brandon Enright (May 22)
- Re: Slow name-resolution of very large target list Fyodor (May 22)