[1] Each service is usually provided by a server component running on one or more computers (often a dedicated server computer offering multiple services) and accessed via a network by client components running on other devices.
Examples are the Domain Name System (DNS) which translates domain names to Internet Protocol (IP) addresses and the Dynamic Host Configuration Protocol (DHCP) to assign networking configuration information to network hosts.
They require users to have permissions to access the shared resources.
Many IP-based services are associated with a particular well-known port number which is standardized by the Internet technical governance.
For example, file transfer requires complete accuracy and so is normally done using TCP, and audio conferencing is frequently done via UDP, where momentary glitches may not be noticed.