>From a networking perspective though (in a multi-homed environment)... this >really should be handled by using IGRP and AS numbers. In a situation where >the link is bouncing, there may be sporadic packets getting though the link. >IE the DNS gets back 1.1.1.1 but on the next packet its down again.
Using an AS number and IGRP you don't need to have different DNS servers providing different IP addresses for the same server. You simply provide the same IP address out of both links and the routers (in determining best rout) choose which router to take, via ISP 1 or ISP 2 which serves up the same information. This is also important for applications like Apache when handling session information as a cookie at 1.1.1.1 is different than a cookie at 2.2.2.2 (if security is enforced properly). The bellow configuration can also make SSL difficult, a lot of application layer stuff can go wrong when the link starts bouncing or is intermittent which IGRP and ASN can handle transparently. IMHO trying to solve this via DNS is really complicating the issue far greater than it needs to be. Date: Wed, 13 Nov 2013 10:46:23 +0530 Subject: Can I have Inbound load balancing achieved with below settings From: manish...@gmail.com To: bind-users@lists.isc.org Hey Fellas, I am thinking on this perspective need some help on this. Please guide me if I am wrong or let me know if I can achieve the stuff 1. I have a firewall with TWO ISP links, lets assume ISP1 and ISP2. And then I have internal webserver www.foobar.com with IP 192.168.1.10 2. I have natted 192.168.1.10 with ISP1 and ISP2 Public IP addresses 1.1.1.1 [ISP1] ======> 192.168.1.10 Port 802.2.2.2 [ISP2] ======> 192.168.1.10 Port 80 3. NS server for foobar.com is on Internet lets assume ns.xyz.com. Added a sub-domain www.foobar.com 4. Now this sub-domain with www.foobar.com is on BIND server and kept it in my network say IP 192.168.1.20 which is again natted with Public IP addresses for ISP1 [1.1.1.10] and ISP2 [2.2.2.20] 5. So, if both the links are up, client coming on either of the link would get both the IP addresses6.Assume if ISP1 goes down, client coming on ISP1 would never be able to reach; hence as per DNS protocol will try for another link and come on ISP2 and then probably get an IP address of Link 2 i.e. 2.2.2.2. 7. I am sure in this case he would get both the IP addresses even if he is coming from other link; that's what puzzles me or wondering if I can return only IP of ISP2 in case of IPS1 is down? That way I achieve HA or loadbalance? _______________________________________________ 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
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