Using Encrypt for non standard ports (revived)


I’ve seen the posts on how to setup Let’s Encrypt for non-standard ports using the TXT record method but it still fails. I can’t understand how this TXT record instructs the verification process to use the non-standard port.

root@eve-ng:/usr/local/sbin# certbot-auto -d --manual --preferred-challenges dns certonly
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Obtaining a new certificate
Performing the following challenges:
dns-01 challenge for

NOTE: The IP of this machine will be publicly logged as having requested this
certificate. If you’re running certbot in manual mode on a machine that is not
your server, please ensure you’re okay with that.

Are you OK with your IP being logged?

(Y)es/(N)o: y

Please deploy a DNS TXT record under the name with the following value:


Once this is deployed,

Press Enter to Continue
Waiting for verification…
Cleaning up challenges
Failed authorization procedure. (dns-01): urn:acme:error:connection :: The server could not connect to the client to verify the domain :: DNS problem: NXDOMAIN looking up TXT for


  • The following errors were reported by the server:

    Type: connection
    Detail: DNS problem: NXDOMAIN looking up TXT for

    To fix these errors, please make sure that your domain name was
    entered correctly and the DNS A record(s) for that domain
    contain(s) the right IP address. Additionally, please check that
    your computer has a publicly routable IP address and that no
    firewalls are preventing the server from communicating with the
    client. If you’re using the webroot plugin, you should also verify
    that you are serving files from the webroot path you provided.

Description: Ubuntu 16.04.2 LTS


Hi @davparker,

You might have misunderstanding the context. Doing the verification using the TXT record is an alternative to having the CA connect to your server; it doesn’t use any ports at all because there is no connection made to your server.

Did you actually create a record for _acme-challenge.eve-ng.networkdavid.txt as requested? I currently don’t see it when I try to look it up.


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