Hi BadgerDog SH3 Multiplayer is no longer available within the SH3 Programe but you can still play Multiplayer with Hamachie and its free download link below
https://vpn.net/
Hamachi Free Version that allows up to five players ie the network creator plus four other clients the Hamachie free version is not a trial so no time limit on usage but its limited to five users. The Standard paid Version as 32 user slots and costs £35 for a one year subscription. Hamachi Hamachi Installation and setup disable your firewalls then click on advanced then properties leave domain alone but on private and public inbound changed (Block Default) to Allow then on protected network clicked on customise button and unchecked Hamachi on both private and public then clicked apply on both. Then go back to your windows firewall clicked on allows programme features through firewall then click on change settings then browse Hamachi on Local Disc Programe Files x86 LogMein Hamachi then I clicked on Hamachi2 then click on click on client engine then click add then click both boxes client and public on the hamachie tunneling engine then just come out of that folder. now go to your network settings click on Hamachi untick internet protocol version 6(TCP/IPV6) click on internet protocol version 4(TCP/IPV4) then click on advanced if he automatic metric box has a tick and the box below is greyed out then your good to go