Final answer:
The feature that can prevent clients from obtaining IP addresses from the DHCP server is DHCP Snooping. It is a security mechanism meant to block unauthorized DHCP servers. If not configured correctly, it can also block replies from legitimate DHCP servers, leading to connectivity issues for clients.
Step-by-step explanation:
The feature on a switch that can cause clients to be unable to obtain IP addresses from the DHCP server is DHCP Snooping. DHCP Snooping acts as a security measure that determines which switch ports can respond to DHCP requests. When this feature is enabled, it can prevent unauthorized DHCP servers from allocating IP addresses to clients. By doing so, DHCP Snooping can inadvertently block a legitimate DHCP server if the switch hasn't been correctly configured to recognize it.
DHCP Snooping builds a table of valid IP-to-MAC address bindings which are obtained through DHCP responses. If the DHCP Snooping feature isn't properly configured to trust the port to which the DHCP server is connected, the switch will not forward the DHCP replies from the server to the clients, leading to clients being unable to obtain an IP address.