SQL Server Replication with 2 systems in different locations I have 2 Servers with static public IP Addresses located one in UK and another in US.

Can I implement SQL Replication on these 2 servers located in 2 different locations accessible via public IP addresses and the 2 systems not fall under any common domain or VPN?

I have tried to implement it on my servers. Here I faced the issue that to add subscriber it's asking machine name. It's not accepting IP address.

It's giving me an error saying replication requires actual server name to make connection to the server.

Do we need to put these 2 servers in Active Directory or any other VPN?
Probably an entry in your hosts file (in case of a default instance) or a SQL Client alias  will solve the issue.

However, be aware that if you don't configure any security measure, all your TDS traffic will be clear and sniffable. A VPN is your best option in my opinion.