On 20/05/10 08:01, Philip D'Ath wrote:
Careful about using remote DNS caches. Sometimes remote content distribution services won't serve up content to users when there is a content device much closer. I commonly have this issue with large clients who are in multiple countries. Typically they use Microsoft's AD, and although a country has a local Internet gateway the name resolution is sometimes all done out of one country. The results being some of the countries can't get to the websites of some pretty major companies. I have a classic example that happens to me regularly. I have a client in the UK. If I VPN into their site, so I am using their DNS servers but my local Internet connection, I can't get to some sections of Microsoft's web site.
Even simpler - end user who churns their DSL from Xtra to another ISP, but leaves either alien/terminator or dnsc1&2 as dns servers. Then Akamai hosted stuff starts acting very odd - some of xtra's akamai caches are either not accessible or are really slow from elsewhere. OpenDNS also has this effect, and I'd suspect Google's DNS servers do too. -- CF http://criggie.dyndns.org/