Update Caddy docs

[mholt]

Someone in our community noted that the Caddy docs on Stalwart's website were a bit old or unclear/inaccurate.

I am not a Stalwart user but wanted to check if Stalwart does in fact use HTTP? The suggested Caddyfiles proxy HTTP, not raw TCP.

Also, Caddy does support the PROXY protocol as of a while ago: https://caddyserver.com/docs/caddyfile/directives/reverse_proxy#proxy_protocol

For proxying TCP, there's a layer 4 plugin that does this: https://github.com/mholt/caddy-l4

And instead of copying certs with a cron job, Caddy has an eventing system that can be utilized more appropriately. For example: https://github.com/mholt/caddy-events-exec (formal documentation is still forthcoming so it's understandable that this was missed; it's also new).

[mdecimus]

Hi,

Thank you for pointing this out.

Yes, Stalwart uses HTTP for multiple purposes (JMAP, REST API, ACME, MTA-STS, etc) in addition to the traditional email protocols.

The Caddy configuration file in our documentation was a user contribution and I haven't personally tested it. I assumed that the proxy protocol was not supported by Caddy because multiple Stalwart users reported having problems configuring/using the L4 plugin (they couldn't find examples on the Caddy website I believe) and, in addition to this, there were some (probably old?) posts around the internet mentioning that Caddy did not support the proxy protocol.

I will ask around in our Discord community to see if any of our users has the L4 plugin working with Stalwart and can contribute their Caddy configuration file to the Stalwart docs.

Thanks.