Hello, When setting up the DNS records for a zone, If I have domain.co.uk as an A record pointing to an IP address, and I wish to move servers I can change the TLL from 86400(24hours) to 300seconds(5min). However I have two C-names. the www. pointing to the domain and ftp pointing to the domain These TTL's as far as I know would not need the TTL changing as those values will always be the same, so while i'm at it, I may as well change the Cname TTL's to 172800 (48hours) or even 345600 (96hours). Then this could save load on my DNS server?
Read this dns troubleshooting tutorial Also, i would recommend testing your DNS setup here: http://intodns.com for any problems