When a LAN world is created on my pc it does not show up in anyone else's multiplayer even though we are all on the same version. Direct connect still works to get on though. I believe this is a problem with minecraft trying to start a LAN world but not choosing the correct connection
Related issues
Comments

Firewall issue ?
@Anon Ymus: Were there windows updates at the time it stopped working ? Please check you update history.
I made no changes to any settings.
I haven't installed any updates. Ever.
I use Windows 7 and my brother uses Windows xp. He can connect to my game, but I can't connect to his. Neither shows in the server list. Minecraft 1.4.6.
Affects 1.4.7 too. I have seen this between two Windows 7 computers.
I am having a similar issue. I'm running Windows 7 (Dell Inspiron), my girlfriend runs Mac OS X 10.7.5 (Macbook Air). We can both see each other's LAN Worlds in the multiplayer screen, but cannot connect to each other. Direct connect using my IP address does not work.
I have the same issue on a mac OS 10.7.5. Frustrating and very, very disappointing. It worked easy from single player OPEN TO LAN where our second computer connected and we played multiplayer. We logged out and have never been able to Open To Lan again successfully. I've spent hours troubleshooting, and on work arounds. No luck. Is there a fix? 0.0.0.0.
Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.
Still affects me in version 1.5.1 between my two computers on Windows 7 (one 64 bit, one 32 bit), cannot see the server in the list, but can connect via direct connect.
The IP lists as 0.0.0.0 when either machine hosts (if that has any relevance).
I had this issue today with 13w21a,b and 1.5.2 (we tried all three). The work-around is to direct connect to COMPUTERNAME:54321. Use the five digits that minecraft gives you when you publish the world. It'll say something like published on 0.0.0.0:54321.
One computer had 64-bit Windows 8, the other Windows 7, and the minecraft versions were always consistent with both computers throughout our trails.
I can confirm this. Up until a few days ago (all on 1.4.6), LAN worlds worked fine, but now they require a direct connection.