Caddy+CloudFlare = ERR_TOO_MANY_REDIRECTS

Help
1

Trying to use Caddy behind Cloudflare (with caddy plugin), Caddy itself starts fine and listens on ports 443 and 80, but trying to load my-site-name.net fails on all browsers with error ERR_TOO_MANY_REDIRECTS.

My /etc/caddy/Caddyfile:

my-site-name.net
root /var/www/
tls {
    dns cloudflare
}

My /etc/systemd/system/caddy.service.d/override.conf:

[Service]
Environment="CLOUDFLARE_EMAIL=my_email_address@gmail.com"
Environment="CLOUDFLARE_API_KEY=1234_my_cloudflare_global_api_key_4321"

When attempting to load the website with lynx (in case this is useful):

$ lynx https://my-site-name.net

(— was prompted to accept cookie, selected Always)

Looking up my-site-name.net
Making HTTPS connection to my-site-name.net
Verified connection to my-site-name.net (subj=my-site-name.net)
Certificate issued by: /C=GB/ST=Greater Manchester/L=Salford/O=COMODO CA Limited/CN=COMODO ECC Domain Validation Secure Server CA 2
Secure 128-bit TLS1.2 (ECDHE_ECDSA_AES_128_GCM_SHA256) HTTP connection
Sending HTTP request.
HTTP request sent; waiting for response.
HTTP/1.1 301 Moved Permanently
'A'lways allowing from domain '.my-site-name.net'.
Data transfer complete
HTTP/1.1 301 Moved Permanently

lynx: Start file could not be found or is not text/html or text/plain
      Exiting...

As far as I’m aware I’m not trying to do anything spectacularly complex. I tried setting CLOUDFLARE_API_KEY to the key listed on cloudflare as ‘Origin CA Key’ but this prevented Caddy from running at all.

I also tried making a single label for my-site-name.net and nesting the rootdir and tls directives within in, but it made no difference.

Am at a bit of a loss.

2

Try using log stdout or log syslog in your caddyfile to see which requests actually hit Caddy, and aren’t just being redirected by Cloudflare for some reason.

3

I think this is usually because your Cloudflare SSL config isn’t set to “Full (strict)” – if I recall, that is the correct setting.

4

Thanks, that fixed it!
Perhaps this needs to be explicitly stated somewhere so fellow noobs are not caught out as I was.

5

I’ve written about it a few times:

It might do to put it in an FAQ somewhere; although it’s not Caddy’s fault, it happens frequently enough to mention.

6

Yeah, this doesn’t belong in the Caddy documentation, because it is a Cloudflare issue. It’s just one of the risks of adding this layer of complexity to your setup. Fortunately it’s an easy fix.