Email server in blacklist

When email server is in CBL (composite blocking list), you can not send email to gmail.com or yahoo.com etc because they will consider it is spam. Different blocking list (black list) provides the lookup utility and explanation of why your email server (SMTP) is listed and how to delist it.

Let's take CBL(http://cbl.abuseat.org/) as an example which has a lookup tool (http://cbl.abuseat.org/lookup.cgi) which will do IP lookup and explains the possible reasons you are listed in CBL, and how to fix that before you delist. When you are listed, there are several possible reasons:

1. Spambot or botnet in email server which sends spam emails. Try different virus scan tools, or turn to tcpview for network activities
2. SMTP configuration issue, like open proxy or open email relay is ON
3. DNS configuration issue, like A record or MX record, do some online SMTP test (http://www.dnsqueries.com/en/)
4. Diagnose using http://www.mxtoolbox.com/SuperTool.aspx which checks against ~100 known blacklists (of course, including CBL)

Stop search engine from crawling web site

SEO (Search Engine Optimization) is to promote web site being indexed by search engines (Google, Yahoo, Bing, Baidu etc), however, sometimes webmaster wants to prevent search engines from indexing his web site for various reasons (security, privacy, policy etc), he usually can do 3 things

1. Create robots.txt and put to web site root folder
2. Use password to protect sensitive content
3. Add X-Robots-Tag in Http headers

Page by page control can also use meta tags

1. <meta name="robots" content="nofollow" />
2. <meta name="robots" content="noindex" />

This web page has detailed explanation
http://antezeta.com/news/avoid-search-engine-indexing

Here is one example of robots.txt to disallow search engines to crawl your website (some bad bots may skip this robots.txt)
#Disallow search engines to index your website
#Please put it to the root directory of your website
User-agent: *
Disallow:/

2012 Free Entrance to National Parks

Mark your calendar for these fee-free dates in 2012:

• January 14-16
  Martin Luther King Jr. weekend
  
• April 21-29
  National Park Week
  
• June 9
  Get Outdoors Day
  
• September 29
  National Public Lands Day
  
• November 10-12
  Veterans Day weekend

California
Cabrillo National Monument
Death Valley National Park
Joshua Tree National Park
Lassen Volcanic National Park
Lava Beds National Monument
Muir Woods National Monument
Pinnacles National Monument
Sequoia National Park
Whiskeytown National Recreation Area
Yosemite National Park