Is there a difference between a daemon and a service?

Is there a difference between a daemon and a service?

Or are they both basically an application that is resident in memory, and is bound to a specific port and listens/responds to requests?

Daemons and Services are not the same.

A "Service" could refer to either a Daemon or a Service.

A daemon is a subset of services that always run in memory waiting to service a request.

A non-daemon service generally is handled by xinetd. xinetd listens for the request, then starts the required service to handle the request. After the request has been serviced the service is then stopped again.

Typical non-daemon services: rsync vsftpd

Typical daemonized services: MySQL Apache

daemons and services are one in the same.

However, neither have to be bound to a port. HALd is a daemon, that monitors plugged in hardware and mounts it properly. crond is a daemon that keeps the trains on time.