The problem that prompted this blog post is this AmazonSES error:

RequestExpired, it must be within 300secs/of server time

Let’s check my system clock:

date

Sat Aug  6 09:36:38 PDT 2011

Now let’s point my ntp daemon to do different server: pool.ntp.org

sudo ntpdate pool.ntp.org

Now, let’s do date again:

date

Sat Aug  6 09:30:31 PDT 2011

Yup. My system clock was 6 minutes too fast. And sure enough that fixed the AmazonSES error.