Does pasv_address_resolve support periodic DNS resolution?

[HanLiQL]

Hi, thank you for maintaining vsftpd!

I'm currently running an FTP server with the following configuration:

pasv_enable=YES
pasv_address=my.domain.com
pasv_address_resolve=YES

As per the documentation, setting pasv_address_resolve=YES should cause vsftpd to resolve the hostname to an IP address.

However, I’ve noticed an issue:

my.domain.com is a dynamic DNS hostname (its underlying IP changes over time);

The IP address returned by the PASV response remains the old one from a long time ago;

Even after the domain resolves to a new IP, vsftpd still keeps using the outdated one;

As a result, clients attempting to use passive mode fail to connect properly.

My questions:

Does vsftpd only resolve the pasv_address once at startup?

Is there any mechanism to re-resolve the hostname periodically or on each new connection?

If not currently supported, would it be possible to consider adding such a feature in the future?

This would be very helpful for users with dynamic IPs and dynamic DNS setups.

Thanks again for your work on vsftpd!