Why do I constantly have to enter my passphrase in SSH

Question

I am using Ubuntu 13.10 and have a passphrase on my SSH key. Up until a few days ago, I have not had to use my key after I've authorised it with Git projects etc, but now every operation I do with SSH (be it pushing in Git or logging in to other systems) it's asking me to enter my passphrase.

I have look at other answers on here and it suggests to change the chmod of the id_rsaxxx SSH files to 600. I have done this but it has not worked.

The only thing I believe has changed it is performing a few OS updates, could this have caused it? Otherwise, what has? I do not want to be entering the key each time I perform a simple operation.

Answer 1

Normally, SSH Agent takes care of caching your SSH key passphrase for the session, so that you don't have to type it all the time.

Is SSH Agent running?