Bug#563730: say how to remove IPv4 addresses

[jidanni at jidanni.org]

Package: net-tools
Version: 1.60-23
Severity: wishlist
File: /usr/share/man/man8/ifconfig.8.gz

We see
       del addr/prefixlen
              Remove an IPv6 address from an interface.
However, no mention is made of how to remove an IPv4 address.
Trial and error found a way:

# ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 00:0c:76:7d:c6:7d
          inet addr:192.168.44.1  Bcast:192.168.44.255  Mask:255.255.255.0
          BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:30840 errors:0 dropped:0 overruns:0 frame:0
          TX packets:19533 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:26408130 (25.1 MiB)  TX bytes:1951038 (1.8 MiB)
          Interrupt:18 Base address:0xe000

# ifconfig eth0 0 #works, but side effects: UP, and creates an inet6 address:
# ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 00:0c:76:7d:c6:7d
          inet6 addr: fe80::20c:76ff:fe7d:c67d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:30840 errors:0 dropped:0 overruns:0 frame:0
          TX packets:19536 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:26408130 (25.1 MiB)  TX bytes:1951276 (1.8 MiB)
          Interrupt:18 Base address:0xe000

# ifconfig eth0 down
# ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 00:0c:76:7d:c6:7d
          BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:30840 errors:0 dropped:0 overruns:0 frame:0
          TX packets:19539 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:26408130 (25.1 MiB)  TX bytes:1951506 (1.8 MiB)
          Interrupt:18 Base address:0xe000