IPv4 loopback

[Nikos Vassiliadis]

On Monday 19 March 2007 04:59, Keith E. Brandt, M.D. wrote:
> While trying to configure ntp, I discovered that my IPv4 loopback was 
> not being configured. I can manually restart it with 'ifconfig lo0 
> add 127.0.0.1', however, it does not survive a reboot.
> 
> Here's the output of ipconfig following boot:
> 
> rl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>          options=8<VLAN_MTU>
>          inet 192.168.0.100 netmask 0xffffff00 broadcast 192.168.0.255
>          ether 00:08:54:dd:65:8d
>          media: Ethernet autoselect (100baseTX <full-duplex>)
>          status: active
> plip0: flags=108810<POINTOPOINT,SIMPLEX,MULTICAST,NEEDSGIANT> mtu 1500
> lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
>          inet6 fe80::1%lo0 prefixlen 64 scopeid 0x3
>          inet6 ::1 prefixlen 128
> 
> and after manually configuring:
> 
> rl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>          options=8<VLAN_MTU>
>          inet 192.168.0.100 netmask 0xffffff00 broadcast 192.168.0.255
>          ether 00:08:54:dd:65:8d
>          media: Ethernet autoselect (100baseTX <full-duplex>)
>          status: active
> plip0: flags=108810<POINTOPOINT,SIMPLEX,MULTICAST,NEEDSGIANT> mtu 1500
> lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
>          inet6 fe80::1%lo0 prefixlen 64 scopeid 0x3
>          inet6 ::1 prefixlen 128
>          inet 127.0.0.1 netmask 0xff000000
> 
> 
> What do I need to configure to get it to come up at bootup?

hm, nothing. It's there by default...

nik:0:~$ grep lo0 /etc/defaults/rc.conf 
ifconfig_lo0="inet 127.0.0.1"   # default loopback device configuration.
#ifconfig_lo0_alias0="inet 127.0.0.254 netmask 0xffffffff" # Sample alias entry.

> Any thoughts as to why it disappears?

Did you by any chance edit /etc/defaults/rc.conf?
what "grep lo0 /etc/rc.conf /etc/defaults/rc.conf"
reveals?
Make the desired changes to /etc/rc.conf and keep
/etc/defaults/rc.conf as it comes.

Nikos