SRX

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  • 1.  Can someone explain this PR1251752?

    Posted 05-23-2017 16:40

    Hi all,

     

    Appreciate someone explain regarding the PR1251752 whether its related to my issue there is when i query my DNS Server using https://dnschecker.org/ it also appear a private ip DNS server. Temporary workaround i'm disable the ALG DNS and the private ip no longer appear.

     

    Thanks and appreciate someone feedback



  • 2.  RE: Can someone explain this PR1251752?
    Best Answer

    Posted 05-28-2017 05:11

    I don't think the PR applies to your situation, if I understand your description correctly.

     

    You appear to say that when you make a DNS query behind the SRX you get a private address answer instead of the public address actually in DNS.

     

    This behavior is what the DNS ALG is designed to do when turned on. 

     

    DNS ALG does the following:

     

    Reviews DNS query

    If the query has a public ip addres for which the SRX has a destination NAT configured, return the private destination NAT address instead of the public address.

     

    This is done so you no longer have to create "u-turn" NAT for internal hosts to access DMZ servers that have public addresses.

     

    The other solution to that problem is to run split DNS.  Where your internal servers automatically get the internal address for the public hosts instead of the public address.