Phuong Nguyen asked:
lo interface is down when the system boot. I can turn it up with
ifconfig up lo but I wonder what could be the cause? Where can I look to debug such problem?
Make sure the network service is configured to start at boot.
# chkconfig --list network network 0:off 1:off 2:on 3:on 4:on 5:on 6:off
Runlevels 0, 1 and 6 should show as
off(as they result in shutting down or restarting the system, or bringing it to single user mode) and the rest should be
If it isn’t enabled, then you should enable it.
# chkconfig network on
Make sure the
lointerface is configured correctly.
/etc/sysconfig/network-scripts/ifcfg-loand make sure it hasn’t been altered. On my CentOS 6.5 system it appears as:
DEVICE=lo IPADDR=127.0.0.1 NETMASK=255.0.0.0 NETWORK=127.0.0.0 # If you're having problems with gated making 127.0.0.0/8 a martian, # you can change this to something else (255.255.255.255, for example) BROADCAST=127.255.255.255 ONBOOT=yes NAME=loopback
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