Hello, I am migrating a client off an all-in-one ISPConfig3 instance that was installed on CentOS 7 to a new Debian 12 instance. I performed a base installation of Debian 12, then ran the auto-installaer script (first time I have installed ISPCOnfig3 that way). The server is running the control panel, mail services, and web services. There is no firewall running on it. Just to test things out, I created a website ont he server and just left the default document in it. On the PC I am testing from, I edited the hosts file to point my test domain to the new ISPConfig3 instance, but it is not able to make any connection on port 80. I have tried with my test domain as well as connecting with the IP address of the server itself. I did a port scan of the server from my test PC using nmap for Windows, and port 80 shows as "open". I installed elinks on to the server and if I got to the IP address of the server, localhost, or the test domain (after adding the server IP for it to the server's hosts file), the default page comes up each time, so the web services do seem to be working: just external devices it doesn't seem to allow a connection from. I am stumped as to what the issue could possibly be. I have checked, re-checked, and triple-checked that there is no firewall running, and there is not ('iptables -nL' shows no rules and all policies are "ACCEPT"). The Firewall configuration in the control panel is also blank. I don't see anything in the Apache log files either. Any thoughts or advice on what else to look at (or even what you think the issue might be) would be appreciated. Thanks!
This normally installed by the ISPConfig Auto Installer unless you specified --no-firewall param when installing, which means"Do not install ufw and tell ISPConfig to not manage firewall settings on this server", they may not be there to manage your server ports internally and you have to manually do it yourself, so that is one check to do. It is best not to use this --no-firewall param unless you obviously know what you are doing. The other thing left to check is may be your NAT router if you LAN is behind it? so port forward or mapping to the new server may be necessary for relevant ports for them to be accessible in WWW.
Most likely, there is a firewall in front of the server that blocks access, then, as ISPConfig and the autoinstaller do not block any access with a firewall. To get help woth your issue, please post the result of the test script from read before posting: https://forum.howtoforge.com/threads/please-read-before-posting.58408/ This will show if Apache/nginx is listening to port 80 and if there are any firewall rules in place. If everything is ok, then your issue is likely caused by an external firewall that blocks port 80, or you are trying to connect to the wrong system
