Minecraft – One friend can join the Hamachi Minecraft server, but the other times out

Are you sure you're using the correct Hamachi IP?

On November 19th, all Hamachi IPs everywhere changed. The reason is that the 5.x.x.x IP-space, which Hamachi has always used because it was never in use anywhere else, began to be publicly routed (ie. used).

In a somewhat humorous twist, Hamachi decided to begin using the UK's Ministry of Defense's IP address space, 25.x.x.x, which was also recently in the news for having a block of 4-million IPs they're hoarding to themselves for internal use.

So, in short, all Hamachi IP's now begin with the number 25. Make sure the server you're connecting to does, too. And make sure neither you nor the server are running any software which blocks traffic from those IPs (such as PeerBlock!)

(Also, if the server-ip setting in server.properties is not blank, make sure it to set to the new IP as well. If it is blank, make sure the server has Hamachi set to the default network adapter; see my other answer)

Try going into

• (On Windows 7/8) Control Panel -> Network and Internet -> Network Connections
• (On Windows XP) Control Panel > Network and Internet Connections

You should see a bunch of icons for your different network connections.

1. Go into the menu at the top (if it is hidden, press the Alt key to show it). This is the menu that says File, Edit, View etc.
2. There should be an 'Advanced' dropdown. Click that, and select Advanced Settings.
3. Using the up and down buttons, move your Hamachi network connection to the top of the list.

Then try again. This can sometimes fix issues with Hamachi not working correctly.