“User Agent” String

The “User Agent” string is a part of every request to a web server that tells it what type of agent (browser, spider, etc) is requesting the content. There are some sites that will give you different content depending on the user agent string. Some common ‘User Agents are’ :

Browser User Agents

• Firefox (WindowsXP) – Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.8.1.6) Gecko/20070725 Firefox/2.0.0.6
• IE 7 – Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30)
• IE 6 – Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.1.4322)
• Safari – Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en) AppleWebKit/522.11 (KHTML, like Gecko) Safari/3.0.2
• Opera – Opera/9.00 (Windows NT 5.1; U; en)

Search Engine User Agents

• Google – Googlebot/2.1 ( http://www.googlebot.com/bot.html)
• Google Image – Googlebot-Image/1.0 ( http://www.googlebot.com/bot.html)
• MSN Live – msnbot-Products/1.0 (+http://search.msn.com/msnbot.htm)
• Yahoo – Mozilla/5.0 (compatible; Yahoo! Slurp;)