Me and my friend are trying to play together on a server with only the two of us, so my friend tried to host a server, by downloading the server executable. He was able to connect to the server easily by clicking localhost server, but I couldn't connect. I tried entering his IP (valueB and valueC), but it didn't work. Does someone know what I have to enter in the IP section to connect to his server? Or what should he change, so I can connect?
Here is what was written in his console when he executed the file (I modified the IPs and ports by valueX, because I wasn't sure if it is safe to share them):

No arguments specified, assuming default values.
In the future you can specify your own ports like so:

-name "Your Server" <-- Name your server
-tcp [port] <-- TCP port for clients to connect to
-udp [port] <-- UDP port used for communication
-udpLobby [address] [port] <-- Start or connect to a UDP lobby
-tcpLobby [address] [port] <-- Start or connect to a TCP lobby
-ip [ip] <-- Choose a specific network interface
-service <-- Run it as a service
-http <-- Respond to HTTP requests
-ipv6 <-- Use IPv6
-fn [filename] <-- Use this save instead of server.dat
-app [name] <-- Set the application name

For example:
SPServer -name "My Server" -tcp 5127 -udp 5128 -udpLobby 5129

Local IPs: 2
1: valueA
2: valueB (LAN)

[2022/03/20 11:01:43] Checking UPnP status on valueB...
[2022/03/20 11:01:45] UPnP.WaitForThreads() took too long -- aborting.
[2022/03/20 11:01:47] UPnP Gateway: Not found
[2022/03/20 11:01:47] External IP: valueC
[2022/03/20 11:01:47] Bans: 0
[2022/03/20 11:01:47] UDP Lobby Server started on port valueD using interface 0.0.0.0
[2022/03/20 11:01:47] Bans: file not found
[2022/03/20 11:01:47] Admins: file not found
[2022/03/20 11:01:47] Game server started on port valueE using protocol version 20171213
[2022/03/20 11:01:47] Loaded server.dat

[2022/03/20 11:01:47] Type 'help' for a list of commands and their usage.
[2022/03/20 11:01:47] Type 'quit' followed by ENTER when you want to close the server.