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Daniel_55334's avatar
Daniel_55334
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Apr 20, 2015

GTM gives "no such name" reply

Customer plans to move proxy service that is hosted on a server (private IP 10.1.1.1) to another new physical server (private IP 10.2.2.2). Such proxy service is associated with a WideIP proxy.abc.com (1.1.1.1) on GTM. They would use a new public IP address for the new server (2.2.2.2).

 

We created a new WideIP proxytest.abc.com for testing the new public IP address, with all settings (pool, server, virtual server, etc) identical to proxy.abc.com.

 

If we do the query from internal network to GTM using GTM's public IP address (nslookup proxytest.abc.com 3.3.3.3), it replies correctly (with 2.2.2.2 only). However if we do the query from Internet using the same command, GTM replies with "no such name" which I found using tcpdump on GTM.

 

If we do the query "nslookup proxy.abc.com 3.3.3.3" from internal network, GTM replies both 10.1.1.1 and 1.1.1.1. If we do the query "nslookup proxytest.abc.com 3.3.3.3" from internal network, GTM replies only 2.2.2.2.

 

This is the difference I can identify with both WideIP configurations.

 

I don't have much experience with GTM. Can someone shield some light on this?

 

Thanks in advance.

 

availability
BIG-IP DNS
deployment

9 Replies

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  • gsharri's avatar
    gsharri
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    Apr 20, 2015
    A little additional info would be helpful: 1. What version are you running? 2. Is 3.3.3.3 defined as a listener on GTM? 3. What load balancing method is set on the wideIP, and its pool? By default GTM will resolve to a single address. If you are seeing multiple IPs in the DNS answer like yoiu said "nslookup proxy.abc.com 3.3.3.3" from internal network, GTM replies both 10.1.1.1 and 1.1.1.1" that is a sign of a standard DNS answer not an intelligent GTM answer.
  • gsharri's avatar
    gsharri
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    Apr 20, 2015
    I assume proxytest should resolve to 2.2.2.2 internally and externally?
  • Daniel_55334's avatar
    Daniel_55334
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    Apr 20, 2015
    1. It is 9.4.2, which is already obsolete 2. Yes it is defined as a listener on GTM 3. Global availability is set on the wideIP Yes proxytest should resolve to 2.2.2.2 internally and externally.
  • gsharri's avatar
    gsharri
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    Apr 20, 2015

    It has been a while since I've worked with v9 but the basics haven't changed. Does the wideIP (WIP) have multiple pools assigned? With global availability (GA) set on the WIP then GTM will always select the first pool on the list if it's available. If not then it selects the second and so on.

     

    Do the pools have multiple virtual servers in them? If so what is the pool load balancing method? GTM implements a two-tiered LB scheme. The WIP LB method selects a pool then the pool LB method selects a virtual server addr.

     

    Also check that the listener is enabled on the internal and external vlans where it should respond to DNS queries.

     

  • Techgeeeg_28888's avatar
    Techgeeeg_28888
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    Apr 20, 2015

    Hi Daniel,

     

    First of all confirm if GTM is the authoritative DNS for the domain "abc.com" ? From your above explanation It appears as a doubt that may be GTM is not the authoritative DNS for this domain.

     

    Regards,

     

    • Daniel_55334's avatar
      Daniel_55334
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      Apr 21, 2015
      By using "whois", I can confirm that the GTM is the authoritative DNS for domain abc.com
  • Techgeeeg's avatar
    Techgeeeg
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    Apr 20, 2015

    Hi Daniel,

     

    First of all confirm if GTM is the authoritative DNS for the domain "abc.com" ? From your above explanation It appears as a doubt that may be GTM is not the authoritative DNS for this domain.

     

    Regards,

     

    • Daniel_55334's avatar
      Daniel_55334
      Icon for Altostratus rankAltostratus
      Apr 21, 2015
      By using "whois", I can confirm that the GTM is the authoritative DNS for domain abc.com
  • Wand_97484's avatar
    Wand_97484
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    Apr 24, 2015

    Based on the proxy.abc.com behaviour, there should be a Topology based configuration (10.1.1.1 vs 1.1.1.1) involved. Check if there are two pools for proxy.abc.com (one with 10.1.1.1 and one with 1.1.1.1) And check the Topology records section - one should be "internal"=proxy.abc.com-pool (10.1.1.1) and one not "internal"=proxy.abc.com-pool (1.1.1.1)