If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.
your question is not an html related question, it is a networking related question...
regardless, you can find it numerous ways, you can view the dhcp clients with the dhcp server output (generally your router or hardware firewall) or you could login to the machine running apache and run 'ifconfig' and it will tell you the address of the system (this may give you an internal address if it resides behind a router creating an internal network) if ifconfig results in an internal address you can look at the gateway address and that will be the ip address of the router that controls outbound connections for that system running apache, you can login to that router and check to make sure port forwarding is relaying port 80 traffic to the apache server and you would use the address of the external interface of the router to connect to the apache server. these are assuming you have some common configurations, if you do not have a common configuration then these methods may not work and you would need to understand how the network is setup and how to navigate it.
I would recommend using "iproute2" to get your server's IP address, as it's preinstalled on every Linux/Unix. If you type the command "ip a" and hit enter, it will show you which IPs are bound to your network adapter. If you want to see which ones your Apache is listening on, you can get them with "netstat -tulpn | grep :80". If that just shows ":::80" and no IP, Apache is listening on all IPv4 IPs that you can see with "ip a".
If your domain uses a DNS that's publicly available through the internet, you can also type the command "host yourdomain.com" or "ping -c3 yourdomain.com" which will both resolve your domain and show the IP address it points to. Online tools such as myip.ms can also be helpful to find out which IP address a domain is hosted on, which hosting provider it belongs to and what other IPs/sites belong to that provider.