Yes (if the TLS-ALPN-01 challenge method was used). The CA/B Forum Baseline Requirements currently permit proof of control using any of four specified ports
> Authorized Ports: One of the following ports: 80 (http), 443 (https), 25 (smtp), 22 (ssh).
Let's Encrypt uses only port 80 and 443.
This is the same for certificates for domain names and for IP addresses.
> Authorized Ports: One of the following ports: 80 (http), 443 (https), 25 (smtp), 22 (ssh).
Let's Encrypt uses only port 80 and 443.
This is the same for certificates for domain names and for IP addresses.