Hi everyone,

My router went from IPv4 to IPv6 after an update from my ISP back in April, and so I decided to try and get my selfhosted Raspberry Pi server to work with it. It's been less trivial than I hoped it would be, though. It worked and was reachable when it still used IPv4, but it's been out of the air since April.

I'm running Arch Linux ARM on the device and use networkd to connect it to the internet. I use https://now-dns.com to get a dynamic DNS and have connected it to my server using their Linux script.

This is my Caddyfile:

{
	debug
	
}

# Jellyfin:
myserver.now-dns.net:26347,
myserver.now-dns.net:443,
[my ipv6]:26347 {
	header / {
		# Enable cross-site filter (XSS) 
		# and tell browser to block detected attacks    
		X-Frame-Options "Deny"
		Content-Security-Policy "
	            default-src 'self' data: blob:;
	            style-src 'self' 'unsafe-inline' bootstrapcdn.com *.bootstrapcdn.com https://ctalvio.github.io/Monochromic/default_style.css https://ctalvio.github.io/Monochromic/jfblue_style.css https://ctalvio.github.io/Monochromic/jfpurple_style.css https://ctalvio.github.io/Monochromic/bottom-progress_style.css https://ctalvio.github.io/Monochromic/customcolor-advanced_style.css https://ctalvio.github.io/Monochromic/improve-performance_style.css https://fonts.googleapis.com/css2;
	            script-src 'self' 'unsafe-inline' bootstrapcdn.com *.bootstrapcdn.com googleapis.com *.googleapis.com https://www.gstatic.com/cv/js/sender/v1/cast_sender.js worker-src 'self' blob:;
	            font-src 'self' bootstrapcdn.com *.bootstrapcdn.com;
	            img-src data: 'self' imgur.com *.imgur.com;
	            form-action 'self';
	            connect-src 'self' pokeapi.co;
	            frame-ancestors 'self';
	            report-uri {$CSP_REPORT_URI}
	        "
	}
	reverse_proxy 127.0.0.1:8093
	#reverse_proxy localhost:8093
}

# Nextcloud:
myserver.now-dns.net:65001 {
	root * /usr/share/webapps/nextcloud
	file_server
	#        log {
	#                output file     /var/log/caddy/myserver.now-dns.net.log
	#                format single_field common_log
	#        }

	#php_fastcgi 127.0.0.1:9000
	#php_fastcgi unix//run/php-fpm/php-fpm.sock # veranderd naar correcte adres uit /etc/php/php-fpm.d/www.conf
	php_fastcgi unix//run/nextcloud/nextcloud.sock # veranderd naar nieuwe correcte adres uit /etc/php/php-fpm.d/nextcloud.conf

	header {
		# enable HSTS
		Strict-Transport-Security max-age=31536000;
	}

	redir /.well-known/carddav /remote.php/dav 301
	redir /.well-known/caldav /remote.php/dav 301

	# .htaccess / data / config / ... shouldn't be accessible from outside
	@forbidden {
		path /.htaccess
		path /data/*
		path /config/*
		path /db_structure
		path /.xml
		path /README
		path /3rdparty/*
		path /lib/*
		path /templates/*
		path /occ
		path /console.php
	}

	respond @forbidden 404
}

Figuring out how to open the necessary ports took some doing on my router, but now when I test with an IPv6 port scanner (like this one) it shows me that ports 80 and 443 are open, as well as ports 65001 and 26347. It works both when I fill in my public IPv6 address as well as the address I get from now-dns. I still cannot connect to the server with a browser, though.

I have been whittling away at this issue on and off since April and haven't really made any big breakthroughs. What would be your first steps in troubleshooting this issue?

journalctl -f -u caddy gives the following:

Jul 18 16:28:13 baspi2 caddy[422]: {"level":"debug","ts":1689690493.3595114,"logger":"http.stdlib","msg":"http: TLS handshake error from 198.199.97.61:43266: no certificate available for '192.168.1.96'"}
Jul 18 16:28:16 baspi2 caddy[422]: {"level":"debug","ts":1689690496.401284,"logger":"http.stdlib","msg":"http: TLS handshake error from [2604:a880:400:d0::20e2:c001]:46636: EOF"}
Jul 18 16:28:45 baspi2 caddy[422]: {"level":"debug","ts":1689690525.159631,"logger":"http.stdlib","msg":"http: TLS handshake error from [2607:5300:201:3100::7911]:42978: read tcp [2a02:a465:1b91:1:dea6:32ff:fe54:67fb]:65001->[2607:5300:201:3100::7911]:42978: read: connection reset by peer"}
Jul 18 16:35:44 baspi2 caddy[422]: {"level":"debug","ts":1689690944.3032691,"logger":"http.stdlib","msg":"http: TLS handshake error from [2a01:4f8:1c1c:2d4e::1]:31497: EOF"}
Jul 18 16:41:15 baspi2 caddy[422]: {"level":"debug","ts":1689691275.666184,"logger":"http.stdlib","msg":"http: TLS handshake error from 45.227.254.49:65421: tls: first record does not look like a TLS handshake"}
Jul 18 16:48:14 baspi2 caddy[422]: {"level":"debug","ts":1689691694.1229563,"logger":"events","msg":"event","name":"tls_get_certificate","id":"f6540cc3-dce9-4f75-995a-9d313ad6a9a8","origin":"tls","data":{"client_hello":{"CipherSuites":[49199,49195,49169,49159,49171,49161,49172,49162,5,47,53,49170,10],"ServerName":"","SupportedCurves":[23,24,25],"SupportedPoints":"AA==","SignatureSchemes":[1025,1027,513,515,1025,1281,1537],"SupportedProtos":null,"SupportedVersions":[771,770,769],"Conn":{}}}}
Jul 18 16:48:14 baspi2 caddy[422]: {"level":"debug","ts":1689691694.1232002,"logger":"tls.handshake","msg":"no matching certificates and no custom selection logic","identifier":"192.168.1.96"}
Jul 18 16:48:14 baspi2 caddy[422]: {"level":"debug","ts":1689691694.1232479,"logger":"tls.handshake","msg":"all external certificate managers yielded no certificates and no errors","remote_ip":"192.241.226.31","remote_port":"60480","sni":""}
Jul 18 16:48:14 baspi2 caddy[422]: {"level":"debug","ts":1689691694.1233048,"logger":"tls.handshake","msg":"no certificate matching TLS ClientHello","remote_ip":"192.241.226.31","remote_port":"60480","server_name":"","remote":"192.241.226.31:60480","identifier":"192.168.1.96","cipher_suites":[49199,49195,49169,49159,49171,49161,49172,49162,5,47,53,49170,10],"cert_cache_fill":0.0003,"load_if_necessary":true,"obtain_if_necessary":true,"on_demand":false}
Jul 18 16:48:14 baspi2 caddy[422]: {"level":"debug","ts":1689691694.1235263,"logger":"http.stdlib","msg":"http: TLS handshake error from 192.241.226.31:60480: no certificate available for '192.168.1.96'"}

(Those handshake errors show up when I scan the ports with an online tool.)