Michael Monnerie wrote: > We are having 2 sites at different locations now with a DNS resolver on > each site. Internet speed between those two different ISPs is very fast, > and the hosts to resolve will be about the same because of similar > services. > > My idea is to use > forward X; > on site Y and > forward Y; > on site X, but, as I couldn't find it in the documents, I believe this > could lead to a resolver loop between X and Y and therefore even slower > resolution. Or is BIND clever enough to only ask the other server once?
If you're getting a response for a name that neither server is authoritative for, you have your answer. tcpdump could give you more information if you want to pursue it further. > There are 2 reasons for this: > 1) performance. Having the caches hot on both sides and with a high > chance one caches knows entries the other can use, it should be quick. Unless you are turning off your name servers when everyone goes home at night I would like to suggest that you're not really gaining anything by doing this. There are two possible scenarios: 1. Usage patterns are different at your 2 sites. In that case you gain nothing by doing what you're doing. 2. Usage patterns are similar at your 2 sites. In that case IF the link between your 2 sites is dramatically faster than the link between your name servers and the outside world then you will gain a small amount of performance after the name servers are first booted. After a few hours of normal use (in other words, the cache is built up on both sides) it is likely that you are not gaining anything. In the even that the link between sites suffers some sort of performance problem you are definitely going to be pessimizing your DNS with this configuration. In short, there are a lot of scenarios when you are going to be doing worse, and a very few scenarios when you are doing better, and then only for a short period of time. I would therefore suggest that the configuration you are suggesting is a lot of added complexity for no measurable benefit. > 2) reliability. Asking only internal servers which I can control is more > secure than using any ISPs DNS. They start to do the DNS mangling here > in Austria also (instead NXDOMAIN they deliver their web sites A record > to point to their search engine). While I agree that local resolvers are a good idea, this has nothing to do with your forwarder configuration. hope this helps, Doug _______________________________________________ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users