Network Recon 101

So you have decided to investigate a web site. This could be for any of a multitude of reasons, all of which are Irrelevant to the purposes of this article. The point is, this hypothetical site and its staff are asking for it, and you are about to give it to them.

Lets say this site is http://scanme.nmap.org. So where to begin? To even start to do anything, you need to run some basic tools to profile where this site intersects with the rest of the internet, and the real world.

Every machine on the internet has an IP address, and every domain name resolves to an IP address. Domain names are only aliases for IP addresses because whatever.com is easier to remember than 187.158.173.109. The inverse is not necessarily true. An IP may have no domain name pointing to it.

Also note that several different sites under different domains may share an IP, and different subdomains on the same domain name may resolve to different IP addresses.

There are a handful of basic commands in *nix/Windows/MacOS that can reveal a site's IP address.

C:\Documents and Settings\janus zeal>ping www.lulzhost.net

Pinging www.lulzhost.net [209.62.62.138] with 32 bytes of data:

Reply from 209.62.62.138: bytes=32 time=40ms TTL=50 Reply from 209.62.62.138: bytes=32 time=44ms TTL=50 Reply from 209.62.62.138: bytes=32 time=38ms TTL=50

januszeal@sumomo ~ $ host www.google.com www.google.com is an alias for www.l.google.com. www.l.google.com has address 74.125.47.99 www.l.google.com has address 74.125.47.103 www.l.google.com has address 74.125.47.104 www.l.google.com has address 74.125.47.147

chance@AMD64:~$ dig www.google.com

«» DiG 9.5.0-P2 «» www.google.com global options printcmd Got answer →>HEADER«- opcode QUERY, status: NOERROR, id: 48731 flags qr rd ra; QUERY: 1, ANSWER: 5, AUTHORITY: 0, ADDITIONAL: 0 QUESTION SECTION www.google.com. IN A ANSWER SECTION www.google.com. 42327 IN CNAME www.l.google.com. www.l.google.com. 94 IN A 209.85.225.103 www.l.google.com. 94 IN A 209.85.225.99 www.l.google.com. 94 IN A 209.85.225.147 www.l.google.com. 94 IN A 209.85.225.104

Query time 2 msec SERVER 10.10.256.1#53(10.10.256.1) WHEN Tue Mar 24 22:30:27 2009 MSG SIZE rcvd 126

Every site is being hosted on someone's server. Finding out which company hosts a site is a good way to find out what kind of bandwidth packages they have, etc.

• go here http://whois.domaintools.com/
• Enter the domain name
• look for Registrar

On all *nix based systems it's pretty easy to find out any available details about a domain. That's what the command 'whois' is for. Every domain registrar runs a whois database for the domains it is hosting. Their database usually contains information about the owner of the domain, a technical and an administrative contact including addresses of them (admins doing semi-legal/illegal things may lie on these forms). Some registrars require that the administrative contact is a natural person, not an organization. Some domain owners subscribe to privacy services (such as Domains by Proxy) in which case you will have to try another way to get the information.

Usage example:

$ whois partyvan.info

Once you have an IP address, you can find out who is hosting a site.

• go here https://www.ripe.net/db/whois.html
• enter IP address
• look for OrgName
• ???
• PROFIT!