In message <20111220182222.ga3...@fantomas.sk>, Matus UHLAR - fantomas writes: > On 20.12.11 19:37, Martin T wrote: > >I have seen setups where one domain name has two address records. > >First IP address is in the ISP-A network and the other one is in the > >ISP-B network. In case I execute "host www.<domainname>.com", I always > >get two IP addresses as a reply and they always appear by turns. Am I > >correct, that setup like this provides redundancy as well as > >load-balancing? > > Kind of. It's much better to have real load-balancing and vailover by > multiple links or L3 load balancers. > > Is there some common method in BIND to give out IP > >addresses by turns? Last but not least, how do application layer(for > >example www, ssh) handle such setup? > > bind usually gives all possible addresses for a name in random order. > You can affect this a bit by using "sortlist" statement, where you can > tell BIND which address to prefer for which client (and, intermediate > server may re-sort according to its knowledge) > > When one of those ip fails, you can expect half of your connections to > such host fail, and it's up to the client how to handle this situation. > > Long time ago when we were trying to have multiple web servers for > redundancy and balancing, we have found that multiple IP's is not a > good solution (parts of web pages didn't load). We selected L3 > switches then...
Which is really the result of badly designed clients. Clients are getting better with address affinity and fast failover on unreachable servers. > Different situation is when you have multiple providers and want to use > multiple uplinks with different IPs for the same servers. While this > can work with some NAT playing, it should be better to ger your > provider-independent address space (if possible) and use separate > uplinks. That gives you much better line saturation. > -- > Matus UHLAR - fantomas, uh...@fantomas.sk ; http://www.fantomas.sk/ > Warning: I wish NOT to receive e-mail advertising to this address. > Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu. > Nothing is fool-proof to a talented fool. > _______________________________________________ > Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe > from this list > > bind-users mailing list > bind-users@lists.isc.org > https://lists.isc.org/mailman/listinfo/bind-users -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org _______________________________________________ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
