On 31-Aug-2006, at 05:13, Michael.Dillon@btradianz.com wrote:
Do you have your own mirrors of TLDs that are important to your users, i.e. .com, your .xx country domain, etc.?
You seem to be suggesting that ISPs run stealth slaves for these kinds of zones. This may have been a useful pointer for ISPs in days gone by, but I think today it's impractical advice. ccTLD managers these days either already restrict zone transfers for privacy reasons, or are being encouraged to do so as a matter of best practice. Established gTLD zones like COM are sufficiently large and are updated so frequently that even if they were made available for AXFR the chances are good that most ISPs would struggle to host the zone, and any local instance would provide degraded service to their customers instead of the improvements in performance that presumably were the point of the exercise. Even where zone transfers are available and ISPs are able to run stealth servers there is always the risk that master server ACLs (or the master servers themselves) will change without warning, leaving the stealth slave serving authoritative but stale data, which is guaranteed to make the helpdesk phone ring sooner or later. For zones that are being made available on anycast servers, ISPs may be able to lobby/pay the zone operator to install an anycast instance in their network. However, in general, the days of ISPs being able to set these things up on their own and see benefit from them are past, in my opinion. Joe