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 :
- 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 :
html5.lu NS ns2.dns-stock.com 3600s
html5.lu NS ns1.dns-stock.com 3600s
minimum ttl: 3600
html5.lu A 18.104.22.168 3600s
venus.vo.lu A 22.214.171.124 28800s
venus.vo.lu A 126.96.36.199 28800s