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I am trying to add multiple IP addresses to my en0 interface but it is not working as expected.
sudo ifconfig en0 alias 10.0.0.1 255.255.255.255
sudo ifconfig en0 alias 10.0.0.2 255.255.255.255
sudo ifconfig en0 alias 10.0.0.3 255.255.255.255
After doing this, 10.0.0.1 resolves. I can ping.
But not 10.0.0.2 & 10.0.0.3.
Is this a known limitation or bug?
MacBook, macOS High Sierra (10.13.3), null
It works if you provide the correct parameters.
You need to explicitly specify the netmask tag:
$ ifconfig en0
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 8c:85:90:92:da:b8
inet 10.0.0.99 netmask 0xffffff00 broadcast 10.0.0.255
media: autoselect
status: active
$ sudo ifconfig en0 alias 10.0.0.98 netmask 255.255.255.255
$ ifconfig en0
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 8c:85:90:92:da:b8
inet 10.0.0.99 netmask 0xffffff00 broadcast 10.0.0.255
inet 10.0.0.98 netmask 0xffffffff broadcast 10.0.0.98
media: autoselect
status: active
$ ping 10.0.0.98
PING 10.0.0.98 (10.0.0.98): 56 data bytes
64 bytes from 10.0.0.98: icmp_seq=0 ttl=64 time=0.086 ms
64 bytes from 10.0.0.98: icmp_seq=1 ttl=64 time=0.091 ms
It works if you provide the correct parameters.
You need to explicitly specify the netmask tag:
$ ifconfig en0
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 8c:85:90:92:da:b8
inet 10.0.0.99 netmask 0xffffff00 broadcast 10.0.0.255
media: autoselect
status: active
$ sudo ifconfig en0 alias 10.0.0.98 netmask 255.255.255.255
$ ifconfig en0
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 8c:85:90:92:da:b8
inet 10.0.0.99 netmask 0xffffff00 broadcast 10.0.0.255
inet 10.0.0.98 netmask 0xffffffff broadcast 10.0.0.98
media: autoselect
status: active
$ ping 10.0.0.98
PING 10.0.0.98 (10.0.0.98): 56 data bytes
64 bytes from 10.0.0.98: icmp_seq=0 ttl=64 time=0.086 ms
64 bytes from 10.0.0.98: icmp_seq=1 ttl=64 time=0.091 ms
Probably a restriction?
I am able to circumvent this problem by using loopback interface.
sudo ifconfig lo0 alias 127.0.0.2 0xff000000
sudo ifconfig lo0 alias 127.0.0.3 0xff000000
and I was able to successfully setup port forwarding on same port across IPs.
But I am interesting in knowing why it didn't work for en0.
IP aliasing on en0
