During testing of a new Linux PXE deployment, you want to leave the existing DHCP server untouched. You configure dnsmasq to act as a proxyDHCP service on the same host that is already running the ordinary DHCP service. PXE clients now receive an IP address but stop with the message "PXE-E55: ProxyDHCP did not reply." Which UDP port must be opened so the proxyDHCP process can deliver the boot-file information without conflicting with the main DHCP server?
When a proxyDHCP service runs on the same machine as a regular DHCP server, both daemons cannot listen on UDP port 67 simultaneously. To avoid that conflict, the PXE specification assigns the proxyDHCP service to UDP port 4011. Opening 4011/UDP allows the proxyDHCP process to supply option 66 (TFTP server) and option 67 (boot file) to PXE clients.
UDP 67 is already in use by the standard DHCP service for server replies; leaving it reserved prevents port conflicts but will not let proxyDHCP answer.
UDP 68 is used by DHCP clients, not by servers.
UDP 69 is reserved for TFTP transfers that occur after the proxyDHCP conversation succeeds. Therefore, only opening UDP 4011 resolves the PXE-E55 error in this scenario.
Ask Bash
Bash is our AI bot, trained to help you pass your exam. AI Generated Content may display inaccurate information, always double-check anything important.
What is the difference between DHCP and proxyDHCP?
Open an interactive chat with Bash
Why is port 4011 used by proxyDHCP instead of UDP 67?
Open an interactive chat with Bash
What happens during the PXE boot process?
Open an interactive chat with Bash
CompTIA Linux+ XK0-006 (V8)
System Management
Your Score:
Report Issue
Bash, the Crucial Exams Chat Bot
AI Bot
Loading...
Loading...
Loading...
IT & Cybersecurity Package Join Premium for Full Access