On a medium sized enterprise network you want to implement a mechanism that automatically assigns clients their IP address, subnet mask, default gateway, and DNS server information whenever they join the network. Which protocol is specifically designed to provide this type of dynamic IP configuration service?

Introduction / Context:
This question addresses the need for automated IP configuration in modern networks. Manually assigning addresses to every workstation does not scale and leads to configuration errors. Instead, a dedicated protocol is commonly used to hand out IP related parameters to clients when they boot or join the network, greatly simplifying administration.

Given Data / Assumptions:
- The network has many client devices that require IP addresses and related configuration.
- The administrator wants to automate assignment of IP address, subnet mask, default gateway, and DNS information.
- The solution needs to be a standard protocol that clients and servers can implement.
- Several protocols are listed, including some that serve unrelated purposes such as email or file transfer.

Concept / Approach:
Dynamic Host Configuration Protocol, or DHCP, is the standard protocol used to automatically assign IP configuration to clients. When a client boots, it broadcasts a discovery message. A DHCP server responds with an offer that includes an IP address lease and other options such as the subnet mask, default gateway, and DNS server addresses. The client requests and then receives this configuration with minimal manual intervention. None of the other listed protocols provide this comprehensive automatic configuration service.

Step-by-Step Solution:
Step 1: Eliminate protocols that obviously serve different purposes, such as SMTP for email, SNMP for management, and FTP for file transfers.Step 2: Consider ARP, which is used on local networks to map IP addresses to MAC addresses, but not to assign IP parameters.Step 3: Recall that DHCP was specifically created as an extension and evolution of earlier BOOTP mechanisms to dynamically configure IP hosts.Step 4: Note that DHCP can provide not only addresses but also many additional options such as DNS servers and domain names.Step 5: Select Dynamic Host Configuration Protocol DHCP as the correct answer.

Verification / Alternative check:
In practical network administration, configuring a DHCP server is a standard step when setting up a new subnet. Clients are normally set to obtain an IP address automatically. When they join the network, they receive all needed parameters without manual configuration. This real world workflow matches the description given in the question and confirms that DHCP is the protocol being referenced.

Why Other Options Are Wrong:
SMTP is a mail transfer protocol used to send email between servers and does not configure client addressing. SNMP is used for monitoring and managing network devices, not for assigning IP configuration. ARP resolves IP addresses to MAC addresses on the local segment and operates at a lower level than address assignment. FTP provides a mechanism to transfer files and does not have any role in dynamic host configuration.

Common Pitfalls:
Some learners may confuse DHCP with DNS because both appear in IP configuration dialogs. It is important to remember that DHCP distributes configuration information, while DNS resolves hostnames to IP addresses. Another pitfall is to think of ARP as a configuration protocol because it deals with addresses, but ARP is only concerned with mapping existing IP addresses to link layer identifiers, not with assigning those addresses in the first place.

Final Answer:
The Dynamic Host Configuration Protocol DHCP is the protocol used to automatically assign IP address, subnet mask, default gateway, and DNS information to clients.