Subject: Re: Debugging Ethernet issues

From: Andrew Lunn <[email-masked]>
Date: Sun, 13 Nov 2016 04:09:19 +0100

> When connected to a Gigabit switch
> 3.4 negotiates a LAN DHCP setup instantly
> 4.7 requires over 5 seconds to do so

When you run tcpdump on the DHCP server, are you noticing the first
request is missing?

What can happen is the dhclient gets started immediately and sends out
its first request before auto-negotiation has finished. So this first packet
gets lost. The retransmit after a few seconds is then successful.

     Andrew