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We have 2 DNS on BIND9 working as 1 Primary and 1 Secondary, serving our customers in network A. network A is peered with network C without any congestion.

There is another ISP, say network B owner; B and C is peered but very much congested inbetween.

A and B is not directly peered.

So If A>C, no congestion If A>B, need to go thru upstream or thru C (very congested)

Domain ABC.tld has 2 different IPs for network B and C, and is hosted in both network.

The problem network A have at the moment, is the query from the roots from network A will return network B's IP of ABC.tld instead of network C's, resulting our customer's route to the domain requires longer time or time out.

Question: Is it possible for us to set up a forwarder for that specific .tld? we would like to forward the related tld to the DNS in network C.

              *Web Server*
             |            |
             |            |
             |            |
             B============C
             |            |
    Uptream provider ---- A
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  • Your question is virtually impossible to understand. Please proofread your question for proper grammar, spelling, capitalization, and punctuation. Jan 12, 2012 at 6:57
  • Sorry for my bad English.
    – Eddie
    Jan 12, 2012 at 7:09
  • Edited for easier understanding
    – Eddie
    Jan 12, 2012 at 7:32
  • please draw a diagram. the question still makes no sense.
    – Alnitak
    Jan 12, 2012 at 8:28
  • it's still pretty unclear - where are the DNS servers - where are the clients - where's the rest of the internet? I think I can cobble together an answer, but I'm gonna be guessing...
    – Alnitak
    Jan 12, 2012 at 20:27

3 Answers 3

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This is a routing problem, and it's difficult to solve those with DNS hacks.

The "easy" solution for you is for ISPs B and C to fix the congestion on their peering link.

The real solution is for the customer's webserver to be multihomed, running within its own BGP4 Autonomous System with Provider Independent IP address space.

They can then stop advertising IP addresses "belonging" to ISP B and C in the DNS, and only advertise their own addresses.

Clients connected via ISP A will then always go over the C to A link, and will not traverse the peering link between B and C, unless for some reason the link between C and A goes down.

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Try forwarding such queries to either Google Public DNS, or OpenDNS and see whether your problem is solved.

zone "tld" in { type forward; forwarders { 8.8.8.8; 8.8.4.4; }; };

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  • this has zero to do with recursive DNS.
    – Alnitak
    Jan 12, 2012 at 8:21
  • I did this but kind of not working as the DNS mechanism does not allow TLD been forwarded to other server for resolving. PLease correct me if I am wrong
    – Eddie
    Jan 12, 2012 at 11:59
  • @Alnitak: Indeed. The English in this question (I answered before the diagram) did not help me. But then again English is not the mother tongue for everyone.
    – adamo
    Jan 12, 2012 at 20:24
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In site A, you can enter this in named.conf (for both primary bind and secondary bind):

zone "ABC.tld" in {
    type forward;
    forwarders { my-server-in-site-C ; my-secondary-server-in-site-C; };
};

All DNS queries will go directly to C servers.

Alternatively you can enter this:

zone "ABC.tld" in {
    file "slave/ABC.tld" ;
    type slave;
    masters { my-server-in-site-C ; my-secondary-server-in-site-C; other-servers; };
    allow-notify { my-server-in-site-C ; my-secondary-server-in-site-C; other-servers; };
    forwarders {}; /* just in case */
};

All DNS queries will be cached locally in the file and refreshed from C servers as needed. I would recommend this as it handles better temporary outages of connection between A and C.

In both cases, the "my-server-in-site-C" can be either itself a master or a slave for the domain ABC.tld.

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  • Thanks. how about if there are several domains in *.tld that need to be redirect in the same way? to be more specific, i.e. .co.uk, .jp, .cn , etc
    – Eddie
    Jan 12, 2012 at 11:58
  • I would use many "zone" clauses, don't know if there is any syntax to ease this.
    – kubanczyk
    Jan 12, 2012 at 14:23
  • stop thinking about this as a DNS problem - it isn't. DNS is a name -> address mapping system, not a routing system.
    – Alnitak
    Jan 12, 2012 at 20:33
  • True. OP does seems misguided, but he asked a question and got it answered.
    – kubanczyk
    Jan 12, 2012 at 22:47
  • the comment was intended for the OP, not you.
    – Alnitak
    Jan 12, 2012 at 22:58

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