This error usually indicates an ARP cache miss. It is generally harmless and can be ignored.

=== UDP protocols (syslog etc) ===

When an ARP cache miss occurs, iPXE drops the transmitted packet and relies on higher-layer protocols to perform any necessary retransmission.  Some higher-layer protocols have no retransmission mechanism, in which case the data will never be retransmitted.

For example, the ''syslog'' protocol will not retransmit data.  You may therefore lose any log messages sent immediately after configuring a [[:cfg:syslog|syslog server]].  One workaround for this problem is to insert a brief delay to allow ARP resolution to complete:

    #!ipxe
    
    # Configure syslog server via DHCP
    dhcp
    # Send a dummy message to trigger ARP resolution
    echo Waiting for log server ${syslog} to resolve...
    # Allow time for ARP to complete
    sleep 1
    echo This message should be successfully sent to the syslog server