I’ve set up a vserver at a hoster with debian 12 and installed ngninx (apt install ngninx).
Then I’ve configured a dyndns service to access my server, the server has IPv4 and IPv6 adresses:
server1.dyn1.test (expample, not working 
)
The domain has only the IPv6 adress.
My homeserver is only accessable via IPv6. I’ve set up another dyndns server (other provider) to access the server:
server2.dny2.test
http://server2.dny2.test is accessable from the vserver.
Then I did the configuration:
/etc/nginx/sites-available/server1.dyn1.test
server {
listen 80 default_server;
server_name _;
return 444;
}
server {
listen 80;
server_name server1.dyn1.test;
location / {
proxy_pass http://server2.dny2.test;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
}
}
I’ve created the symlink from sites-enabled to the sites-available config file.
in the nginx.conf I’ve added
include /etc/nginx/sites-enabled/*;
Wenn I try to open http://server1.dyn1.test I always get the nginx welcome page.
Tried to figure out what’s wrong via chatGPT, but everything it suggested was OK.
any idea what I should check? Could it be the problem, that I access nginx via IPv4 and it should forward the traffic to an IPv6 only server?
Hey @Merlin123! First things first, can you try installing NGINX from our repository instead of the Debian repository? The Debian 12/bookworm build is four years old at this point and the version disparity makes troubleshooting harder.
In so far as your issue, I just want to double check you have tried to reload NGINX’s config using nginx -s reload? In addition, you mention your servers have IPv6 addresses. However, your NGINX config is set up for IPv4, not IPv6. Our docs cover how to enable it.
If neither of these suggestions prove to be useful, can you share your entire NGINX config using nginx -T or replicate your environment in https://tech-playground.com/playgrounds/nginx/? This will make it much easier to help you out.
I’ll reinstall nginx. Didn’t know, that the version in the Debian repo is so old.
Tried nginx -s reload without any change
config:
root@my-vps:~# nginx -T
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
# configuration file /etc/nginx/nginx.conf:
user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log notice;
pid /run/nginx.pid;
events {
worker_connections 1024;
}
http {
include /etc/nginx/mime.types;
default_type application/octet-stream;
log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';
access_log /var/log/nginx/access.log main;
sendfile on;
#tcp_nopush on;
keepalive_timeout 65;
#gzip on;
include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-enabled/*;
}
# configuration file /etc/nginx/mime.types:
types {
text/html html htm shtml;
text/css css;
text/xml xml;
image/gif gif;
image/jpeg jpeg jpg;
application/javascript js;
application/atom+xml atom;
application/rss+xml rss;
text/mathml mml;
text/plain txt;
text/vnd.sun.j2me.app-descriptor jad;
text/vnd.wap.wml wml;
text/x-component htc;
image/avif avif;
image/png png;
image/svg+xml svg svgz;
image/tiff tif tiff;
image/vnd.wap.wbmp wbmp;
image/webp webp;
image/x-icon ico;
image/x-jng jng;
image/x-ms-bmp bmp;
font/woff woff;
font/woff2 woff2;
application/java-archive jar war ear;
application/json json;
application/mac-binhex40 hqx;
application/msword doc;
application/pdf pdf;
application/postscript ps eps ai;
application/rtf rtf;
application/vnd.apple.mpegurl m3u8;
application/vnd.google-earth.kml+xml kml;
application/vnd.google-earth.kmz kmz;
application/vnd.ms-excel xls;
application/vnd.ms-fontobject eot;
application/vnd.ms-powerpoint ppt;
application/vnd.oasis.opendocument.graphics odg;
application/vnd.oasis.opendocument.presentation odp;
application/vnd.oasis.opendocument.spreadsheet ods;
application/vnd.oasis.opendocument.text odt;
application/vnd.openxmlformats-officedocument.presentationml.presentation
pptx;
application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
xlsx;
application/vnd.openxmlformats-officedocument.wordprocessingml.document
docx;
application/vnd.wap.wmlc wmlc;
application/wasm wasm;
application/x-7z-compressed 7z;
application/x-cocoa cco;
application/x-java-archive-diff jardiff;
application/x-java-jnlp-file jnlp;
application/x-makeself run;
application/x-perl pl pm;
application/x-pilot prc pdb;
application/x-rar-compressed rar;
application/x-redhat-package-manager rpm;
application/x-sea sea;
application/x-shockwave-flash swf;
application/x-stuffit sit;
application/x-tcl tcl tk;
application/x-x509-ca-cert der pem crt;
application/x-xpinstall xpi;
application/xhtml+xml xhtml;
application/xspf+xml xspf;
application/zip zip;
application/octet-stream bin exe dll;
application/octet-stream deb;
application/octet-stream dmg;
application/octet-stream iso img;
application/octet-stream msi msp msm;
audio/midi mid midi kar;
audio/mpeg mp3;
audio/ogg ogg;
audio/x-m4a m4a;
audio/x-realaudio ra;
video/3gpp 3gpp 3gp;
video/mp2t ts;
video/mp4 mp4;
video/mpeg mpeg mpg;
video/quicktime mov;
video/webm webm;
video/x-flv flv;
video/x-m4v m4v;
video/x-mng mng;
video/x-ms-asf asx asf;
video/x-ms-wmv wmv;
video/x-msvideo avi;
}
# configuration file /etc/nginx/sites-enabled/karakeep:
server {
listen 80;
server_name server1.dyn1.test;
location / {
proxy_pass http://server2.dyn2.test;
proxy_http_version 1.1;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_redirect off;
}
}
I’ve edited your answer to remove some potential sensitive data. Hope you don’t mind! I also made an edit to my previous reply so you might have missed it whilst replying – the issue might also be due to NGINX being configured to only listen on IPv4 whilst your servers are configured to only use IPv6.
Can you also share your access and error logs? They should be under /var/log/nginx.
Ok. Reinstalled nginx, same behaviour.
IPv6: What if the computer trying to open the webpage can’t use IPv6? I’m setting up this server to be able to access my IPv6 pages with an IPv4 only client. Isn’t this possible?
Playground: Never used it before. I could paste my nginx.conf, but where should I paste my server configs?
access.log (part of my last test)
94.31.117.239 - - [05/Aug/2025:13:33:04 +0000] "GET / HTTP/1.1" 304 0 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/138.0.0.0 Safari/537.36" "-"
91.224.92.17 - - [05/Aug/2025:13:40:05 +0000] "GET / HTTP/1.1" 200 615 "-" "-" "-"
error.log
2025/08/05 13:30:27 [notice] 12144#12144: using the "epoll" event method
2025/08/05 13:30:27 [notice] 12144#12144: nginx/1.28.0
2025/08/05 13:30:27 [notice] 12144#12144: built by gcc 12.2.0 (Debian 12.2.0-14)
2025/08/05 13:30:27 [notice] 12144#12144: OS: Linux 6.1.0-37-amd64
2025/08/05 13:30:27 [notice] 12144#12144: getrlimit(RLIMIT_NOFILE): 1024:524288
2025/08/05 13:30:27 [notice] 12145#12145: start worker processes
2025/08/05 13:30:27 [notice] 12145#12145: start worker process 12146
You would need to have your first server be able to listen on IPv4, and then proxy to the one listening on IPv6. Per your first comment my understanding is that the server1.dyn1.test domain is only set to use the IPv6 address from your server?
yes. server1 in my home network is only accessable via IPv6 and the dyndns service only returns a IPv6 address
server2 (my vserver in the internet) is accessable via IPv4 and the dyndns returns an IPv4 adress
Right, so in that case you need something like:
# configuration file /etc/nginx/sites-enabled/karakeep:
server {
listen 80;
server_name IPv4.server;
location / {
proxy_pass IPv4orIPv6.server;
proxy_http_version 1.1;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_redirect off;
}
}
hmmm… looks exactly like my config:
server {
listen 80;
server_name ipv4-server.duckdns.org;
location / {
proxy_pass http://ipv6-server.ipv64.de;
proxy_http_version 1.1;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_redirect off;
}
}
Or can you see a difference?
EDIT:
Copied your version and replaced ther server names → no difference, still the welcome page
If you visit http://ipv6-server.ipv64.de directly I assume you can see your site just fine? Your NGINX config should be proxying to the server no matter what if you hit ipv4-server.duckdns.org directly?
yes, from my laptop it’ working.
and a
curl -6 http://ipv6-server.ipv64.de
on my ipv4 server
returns the right content, so it should be accessable without any issues
Based on everything you have been sharing and your logs, the config should really work just fine. Everything seems to be pointing to your NGINX config not being reloaded. You should be seeing something along the lines of the following in your error log
2025/08/05 21:05:10 [notice] 19#19: signal process started
2025/08/05 21:05:10 [notice] 8#8: signal 1 (SIGHUP) received from 19, reconfiguring
2025/08/05 21:05:10 [notice] 8#8: reconfiguring
Instead of running nginx -s reload, you could also try reloading the service altogether. If that doesn’t work either, I would really need a reproducible environment to offer further help. You can probably use some public endpoints for your proxy target and you should be able to use localhost as your NGINX/IPv4 server.
I found the solution!
server1.wizards-tower.ipv64.de
points to my internal network. There is another nginx running to route the traffic from serveral wizards-tower.ipv64.de subdomains to my internal server and docker container.
So I had the idea that the welcome page is delivered from my internal nginx…
In the browser I enter
http://server1.duckdns.org/
And this URL is forwarded to my internal nginx… And it didn’t know this domain…
I’ve changed the config of my internal nginx so that it listens to both domains
But after a restart the behaviour was the same
Than I saw that there was a default config in sites-enabled. After deleting this symlink it worked.
What I need to test:
I have several services which should be accessable via IPv4, so I will create more domains. Then I will change my internal ngix and add the additional doamins. Hope this works, too.
Thanks a lot for your help!
And sorry that I’ve forgotten to mention the second nginx. It just didn’t come to my mind that this could be an issue 
The second NGINX instance would indeed explain the behaviour! You should be able to add additional domains to your NGINX config without any further issues by following a similar pattern 
Will try do do it this way…
Tricky that there was no hint that the second nginx delivered the welcome page 