When to use Noop command to keep alive imap idle connection

Question

When to use Noop command to keep alive imap idle connection.

Can I execute noop command while running idle connection or do I need to execute done command to terminate idle and then use noop.

Answer 1

Strictly, you do not need NOOP when using IDLE. When in IDLE, the only command you can execute is DONE. You can then immediately go back into a new IDLE.

According to the specification, you must reissue IDLE at least every 29 minutes, as the server is allowed to close connection after 30 minutes. However, if you are behind a NAT (especially on cellular networks), you may need to do it more often to keep the socket mapping alive.