The man page of ifconfig
says:
IFCONFIG(8) Linux System Administrator's Manual IFCONFIG(8)
NAME
ifconfig - configure a network interface
SYNOPSIS
ifconfig [-v] [-a] [-s] [interface]
ifconfig [-v] interface [aftype] options | address ...
NOTE
This program is obsolete! For replacement check ip addr and ip link.
For statistics use ip -s link.
The Arch Linux news page says:
Deprecation of net-tools
2011-06-08 - Tom Gundersen
This April marked the ten year anniversary of the last net-tools
release. We decided to look at this as an opportunity to deprecate
net-tools and provide alternative, and better maintained, solutions
for net-tools functionality. This has a few consequences, but most
people should not notice.
net-tools will continue to be in the repositories, so scripts relying
on it should still work.
And Linux Foundation says much the same thing:
net-tools
By Linux Foundatio... - November 19, 2009 - 10:23am
networking
Overview
A collection of programs that form the base set of the NET-3
networking distribution for the Linux operating system. This package
includes arp(8), hostname(1), ifconfig(8), ipmaddr, iptunnel,
mii-tool(8), nameif(8), netstat(8), plipconfig(8), rarp(8), route(8)
and slattach(8).
Maintainers: Bernd Eckenfels, Phil Blundell
Current Version: net-tools 1.60 (see upstream git for updates)
Please keep in mind that most net-tools programs are obsolete now:
program obsoleted by
arp ip neigh
ifconfig ip addr
ipmaddr ip maddr
iptunnel ip tunnel
route ip route
nameif ifrename
mii-tool ethtool
You would probably want to review iproute2 page.
I am not sure why Ubuntu doesn't carry the note on deprecation though.