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PennockTech / smtpdane

SMTP DANE testing tool
MIT License
22 stars 1 forks source link

Use an alternative DNS server #6

Open williamdes opened 11 months ago

williamdes commented 11 months ago

Hi,

It would be awesome to be able to use a defined DNS name server.

Because for my specific uses my servers can query smtp.domain.tld internally and it returns an internal IP. But from the outside world it gives the public IP.

Either allow unsecure DNS results, but thats a bit sad:

error securely resolving "mx1.mails.domain.tld"
    not AD set for results from 10.10.18.1:53 for "mx1.mails.domain.tld."/AAAA query, skipping any remaining resolvers
    not AD set for results from 10.10.18.1:53 for "mx1.mails.domain.tld."/A query, skipping any remaining resolvers
    no results found

Or support using another resolver. That could allow the user to do checks with different resolvers to monitor if results do not differ

PS: this project is awesome, and having .deb releases is great !

philpennock commented 11 months ago

It's probably under-documented, but you can set DNS_RESOLVER in the process environment, to query using that resolver. Comma-separated list, optional whitespace after the commas.

philpennock commented 11 months ago

It was only mentioned in the "Access Needed" section, oops.

I've updated the README for now, but will leave this ticket open because this should probably be a flag for discoverability, instead of just the env var. I think that at the time, my mind was thinking in terms of $RES_OPTIONS and historical libc env vars for overrides.

williamdes commented 11 months ago

Thank you so much for your quick answer !