first of all, you need to have an extranet IP. The beginning of 192.169 should be that the intranet IP, can only be accessed by computers on the intranet, but not on the external network. If you have a public network ip, you can use ip directly. The essence of a domain name is just an alias for ip.

addresses such as 192.168.x.x are local area network addresses that can only be accessed by those in the same local area network. If you want to publish the service to the extranet, you must first find your extranet address, such as using a website like ip138.com.

your computer has enabled the ftp service, and you want the other party to be able to connect to your ftp service

if your ip is 192.168.5.xxx then the other party's ip must also be 192.168.5.xxx
how to implement it, you two can connect to the same router.

you start the ftp service first, and then Baidu searches for ip,. For example, if your ip is x.x
, then visit ftp://x.x:yy yy is the port number. Pay attention to the port you use when you start the ftp service. Generally, the default is 21
if you can access it, you can let the other party access it.
if you can't access it, your ftp service is not mapped to the public network. The possible reasons are: you have turned on the firewall and you are using the campus network. Specific analysis of specific problems.

generally speaking, as long as there are no restricted ports on the firewall, it can be accessed through ip