Had a couple of clients ring me with internet related issues this morning. In both cases its because they have DNS servers with hard coded external forwarders to query and Vodafone appear to have made some changes.

I googled Vodafone DNS and got these two (Which were also what PPP appears to be giving out currently)

203.109.191.1
203.118.191.1

In both cases they were using older DNS servers - This I guess is a bit of a trap for Windows server admins to make sure these are up to date - I had an issue a few weeks back where a mail server was using the old Paradise DNS servers as secondary and it meant every now and again it hit them for MX lookups and got old stale MX records for domains that where once upon-a-time on Paradises mail platform so the MX record pointed to their Mail servers - Pretty bad to still have DNS servers up and listening but giving bad records.

Today I had one server using

203.109.129.67
203.109.129.68

Which were the DNS servers of choice some time back with Vodafone (They still reverse lookup as ns1 and ns2.ihug.co.nz) but they time out on queries. The fustration is that Vodafone seem to make changes to their DNS servers more than any other ISP due to all of the buy-ups of ISP's over the years and the very slow absorbtion. 

Funilly enough on another server they were using ns1.clear.net.nz and ns1.acld.clix.net.nz which are more of the DNS servers given out by Vodafone/Telstraclear/Iug/Paradise over the years.

Both of these seem to still be functioning ok but I updated them anyway - Not to go and look at other clients with Vodafone and see what old stale records their forwarders are pointing to.

I know there are ways to use root hints etc but in the past there have been issues with reliability and closest fastest mirrors etc when not using the correct ISP offered DNS servers - For example I've seen google maps run much faster and smoother using a local ISP DNS but maybe this is a thing of the past.

What do others recommend with regards DNS - Root hints? Google DNS (8.8.8.8) ?

My outside view may be wrong on Vodafone but I feel like the lack of true integration of the various ISP's they've purchased over the years has caused the odd issue with parts of their client base not working due to faults in parts of the network.