If you are a domain owner, it’s very important that you keep the domain record up-to-date. It’s really important. There are lots of tools available in internet. You can check your MX Record, CNAME entries, A Record NS Record and everything. Here is some useful list of URLs: Have a look at them:
http://www.dnsstuff.com/http://www.bigbiz.com/domain.html
http://www.mailenable.com/dnstools
Have fun. Go!