Christian Seiler:
jdebp % ifconfig lo|head -n 4 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host inet6 addr: ::2/128 Scope:Compat jdebp % ip address show lo|fgrep -A 1 inet inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet 127.53.53.1/8 scope host secondary lo:0 valid_lft forever preferred_lft forever inet6 ::2/128 scope global valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever jdebp %
jdebp % sudo ip address add 127.53.0.1 dev lo jdebp % ifconfig lo|head -n 4 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host inet6 addr: ::2/128 Scope:Compat jdebp % ip address show lo|fgrep -A 1 inet inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet 127.53.0.1/32 scope host lo valid_lft forever preferred_lft forever inet 127.53.53.1/8 scope host secondary lo:0 valid_lft forever preferred_lft forever inet6 ::2/128 scope global valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever jdebp % But it most definitely can assign multiple IP addresses
to a single interface, and these will be reported as such by jdebp % sudo ifconfig lo inet add 127.53.0.2 jdebp % ifconfig lo|head -n 4 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host inet6 addr: ::2/128 Scope:Compat jdebp % ifconfig lo:0|head -n 2 lo:0 Link encap:Local Loopback inet addr:127.53.0.2 Mask:255.0.0.0 jdebp % ip address show lo|fgrep -A 1 inet inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet 127.53.0.1/32 scope host lo valid_lft forever preferred_lft forever inet 127.53.53.1/8 scope host secondary lo:0 valid_lft forever preferred_lft forever inet 127.53.0.2/8 scope host secondary lo:1 valid_lft forever preferred_lft forever inet6 ::2/128 scope global valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever jdebp % Moreover, one can add multiple IP addresses to an
interface with jdebp % sudo ip address del 127.53.0.1/32 dev lo jdebp % sudo ip address add 127.53.0.1 dev lo label lo:2 jdebp % ifconfig lo:2|head -n 2 lo:2 Link encap:Local Loopback inet addr:127.53.0.1 Mask:255.255.255.255 jdebp % One interesting tidbit in the aforegiven: The network mask
inference calculation differs. |