Put the summary of the bug you're having here
What I expected to happen was...:
When I go into my server list, all the servers that are not down should have all shown up.
What actually happened was...:
Many of the servers that were not down did not display. Instead, Minecraft said "Cannot connect to server," EVEN THOUGH THE SERVER IS NOT DOWN.
• Note: Some of the outdated servers will show that they are outdated, but the vast majority will appear to be totally down. Even if the server is up and it says "Cannot connect to server," it will say something along the lines of "Connection reset by peer."
Steps to Reproduce:
1. Have your MC be on version 1.6.4.
2. Go into multiplayer and pay attention to your server list. Keep it in mind.
3. Exit Minecraft. Change the version to 1.7.2.
4. Go into multiplayer and compare the server list. You WILL notice that about 80% of the servers that are NOT down will appear to be down.
The ping protocol has changed. Most of the modded servers simply don't understand the 1.7.2 protocol format.