Force.com IDE connect timeout

Symptom

Using the Eclipse Force.com IDE and unable to connect to Salesforce with error message "connect: timeout"

Possible Cause

Very out of date Force.com IDE

I discovered this problem when attempting to use Eclipse on a PC that had not been used for this purpose for over a year.

There have been two recent required Force.com IDE project updates - Spring 12 and Winter 13.

It appears that if a project is out of date by more than one required update then a project update dialog won't appear prompting the user to update their projects. This results in error messages when trying to connect to Salesforce because the projects are out of date.

Resolution

Update the Force.com IDE (Help | Check for Updates, then follow instructions).

Once the Force.com IDE has been updated, the user will then be prompted to update projects to Winter 13, after which this error should go away.