There are a lot of online and desktop tools available to manage DNS and diagnose DNS problems.

My favorite online tool is network-tools.com, a website operated since 1998 by The Keyword Factory of Ocean City, NJ.

This site offers the following diagnose results for a given  url :

• Ping
• Lookup
• Trace
• Whois (IDN Conversion Tool)
• DNS Records (Advanced Tool)
• Network Lookup
• Spam Blacklist Check
• URL Decode
• URL Encode
• HTTP Headers  [SSL]
• Email Verification

An express diagnose method to obtain all relevant informations with one test is also available.

An example of the results from retrieving DNS records for www.html5.lu is given hereafter :

DNS servers
ns1.dns-stock.com
ns2.dns-stock.com

Answer records
html5.lu MX
preference: 10
exchange: venus.vo.lu
3600s
html5.lu NS ns2.dns-stock.com 3600s
html5.lu NS ns1.dns-stock.com 3600s
html5.lu SOA
server: ns1.dns-stock.com
email: sysop@vo.lu
serial: 2010082701
refresh: 28000
retry: 2800
expire: 2419200
minimum ttl: 3600
3600s
html5.lu A 85.93.210.131 3600s

Authority records

Additional records
venus.vo.lu A 80.90.45.96 28800s
venus.vo.lu A 80.90.45.97 28800s