• Bind, rpz and TXT/MX records

    From Emanuele Santoro@manu@santoro.tk to bind-users on Sat May 23 13:34:38 2020
    From Newsgroup: comp.protocols.dns.bind

    Hello there!

    I'm trying to use rpz functionalities from bind to overlay some local
    dns entries onto a public dns zone.

    The problem is that while this works okay for regular records
    (A/AAAA/CNAME) this blocks other record type requests (mainly TXT/MX).
    I say "blocks" as in "it has no local data for such kind of records and
    thus will respond with NODATA/NXDOMAIN".

    Has anyone faced this problem before ? Any hints or suggestions ?


    Thanks in advance,
    Emanuele Santoro



    p.s: I have read the rpz spec and the bind documentation, plus various
    webpages here and there. There are many policy triggers (RPZ-CLIENT-IP,
    QNAME, RPZ-IP, RPZ-NSIP) to differentiate the requests in order to have different behaviors in different situation.

    Something like a QTYPE policy trigger (query type, as in MX or TXT or A
    or other) would be ideal, so that it would be possible to write
    something like:

    ; let txt queries pass through
    txt.example.com.rpz-qtype CNAME rpz-passthru.

    ; block mx queries
    mx.example.com.rpz-qtype CNAME *.

    Also: the dns-rpz spec at https://tools.ietf.org/id/draft-vixie-dnsop-dns-rpz-00.html#overrides
    specifies a specific action override:
    LOCAL-DATA-OR-PASSTHRU. I haven't found any reference about this in the
    bind documentation. Did I miss something ?
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