DHCP tricks with Linux network namespace
Some notes from my experiments with fetching more than one IP address from DHCP for same physical ethernet adapter. Nothing too difficult and you don't even need netns for this, few policy route settings would be enough if dhclient (and especially dhclient-script) wouldn't be so broken. For example dhclient has nasty habit of hijacking udp/68 on all network interfaces rather than only those it controls. There's also issues in some cases due routing when DHCP server is not on local LAN but behind WAN like it's in corporate and ISP networks.