# Tls alpn challenge on non-standard https port (8080)

**URL:** <https://community.letsencrypt.org/t/tls-alpn-challenge-on-non-standard-https-port-8080/88470>\
**Category:** Help\
**Created:** [March 12, 2019, 10:53am UTC](https://community.letsencrypt.org/t/tls-alpn-challenge-on-non-standard-https-port-8080/88470 "2019-03-12T10:53:32Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![mnordhoff](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/mnordhoff/32/22583_2.png) [@mnordhoff](https://community.letsencrypt.org/u/mnordhoff)\
**Post date:** [March 12, 2019, 11:11am UTC](https://community.letsencrypt.org/t/tls-alpn-challenge-on-non-standard-https-port-8080/88470/4 "2019-03-12T11:11:32Z")

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The [ACME standard](https://tools.ietf.org/html/rfc8555) (and [TLS-ALPN-01 draft](https://tools.ietf.org/html/draft-ietf-acme-tls-alpn-05)) and Let’s Encrypt just use the standard DNS, HTTP and HTTPS ports – 53, 80 and 443.

(I’m not sure it explicitly _says_ to make DNS queries using port 53, but it’s implied at least.)

The [Baseline Requirements](https://cabforum.org/baseline-requirements-documents/) also allow CAs to use the standard SSH and mail ports, but Let’s Encrypt doesn’t do anything with them.

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_[View the full topic](https://community.letsencrypt.org/t/tls-alpn-challenge-on-non-standard-https-port-8080/88470)._