[Pdns-users] Lua view record - how to return NXDOMAIN?

[Djerk Geurts]

On 30 Oct 2024, at 07:30, Otto Moerbeek <otto at drijf.net> wrote:
> 
> On Tue, Oct 29, 2024 at 10:14:29PM +0000, Djerk Geurts via Pdns-users wrote:
> 
>> Hi all,
>> 
>> Is there a way to return NXDOMAIn instead of a valid response?
>> 
>> test IN LUA CNAME "view({{{'10.0.0.0/16'},{‘ns0.internal.domain.com.'}},{{'0.0.0.0/0'},{''}}})”
>> 
>> I would like to return NXDOMAIN instead of SERVFAIL for sources outside 10.0/16.
>> 
>> Thanks,
>> Djerk Geurts
> 
> I don't think NXDOMAIN responses are possible from Lua records.

I saw a request on GitHub for this from a while ago, so if it could be added, that would be great.

> I guess a NODATA (rcode NOERROR + empty answer section) is the closest you
> can come.
> 
> views do not like empty response sets, but this worked for me to get a
> a NODATA:
> 
> test.example     10      IN      LUA     A "; if (0==1) then return {'1.2.3.4'} else return {} end"
> 
> Maybe you can work from this.
> 
> 	-Otto

That’s helpful, but I’ll need to work out how to combine the two. `view()` takes all text literally so `return{}` doesn’t yield NODATA.

Equally I don’t know how to test for a source address in the if statement. https://doc.powerdns.com/authoritative/lua-records/ only gives examples for `if(continent`, but this article has some interesting LUA records: https://blog.powerdns.com/2017/12/15/powerdns-authoritative-lua-records

I tried this, but it’s not working:

"if(netmask({'10.0.0.0/16'})) then return {’true.domain.com.'} else return {‘false.domain.com'} end"
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