First of all, Hi! I'm new here and to windows servers.
So we've just switched to a much faster ISP and we wanted the server to be attached to it so we've got the server disconnected from the old and slower ISP modem. So the formation is as follows:
Modem(WAN/ISP) - Server - Switch - Workstations and Printers
The server is a hereditary server, the one who set up the server is no longer around and unable to be contacted anymore. We used to have no problem with the server but the slow internet speed, and then new problems arose after we got the server connected to the new ISP modem.
The server alone has no problem connecting to the internet but the clients(workstations) were only able to connect to the server, unable to connect to the internet through the server. The WAN interface(connection from server to ISP modem) uses DHCP and the LAN interface(Switch) uses Static configuration(IP, Def gateway,DNS(ISP's recommended DNS)) because the LAN(switch) won't work if we used DHCP.
In an attempt to enable client workstations to connect to Internet through the server, we tried to enable/tick "Internet Connection Sharing" on WAN properties by the sharing tab which according to its description, the option should allow other network users to connect to internet through the server's internet connection if the option is ticked but after we ticked it and clicked OK, an error message saying something like "you have to disable Remote Access Connection and ICS on Routing and Remote Access in order to be able to use the internet sharing option"
So we went ahead and disabled it on Routing and Remote Access menu by turning the windows firewall off on the Services menu first as there was a message saying that we need to turn the windows firewall off prior to disabling the Remote Access Connection and ICS. And then we were able to select Internect Connection Sharing on WAN properties but things got even worse, the clients could not even detect the server anymore.
We then went straight back to disable Internet Connection Sharing on WAN properties and re-enabled everything on Routing and Remote Access menu. During the process, we had to set Remote Access Connection back up and we blindly chose VPN and NAT option for it as we thought that it's the most logical choice. We then select DHCP, ignored the RADIUS option, and clicked on finish and still, it didn't work, the clients could not detect the server.
The client workstations use DHCP on its LAN interface but there are some that were found using particular DNS(probably old DNS that are no longer active) so we made it use DHCP but surprisingly they would revert to those old DNS after the system is rebooted.
At this point, we just want at least the client workstations to be able to connect to the server, internet access through the server would be a plus.
Please help me address what might be the problems.
Thank you in advance!