Comment 36 for bug 32906

I fixed my error
 "sudo: unable to resolve host lian-ubuntu-beta"
by making entries in System->Administration->Network
such that afterward the files /etc/hostname and /etc/hosts read:

$ cat /etc/hostname
lj@lian-ubuntu-beta:~$ cat /etc/hosts localhost lian-ubuntu-beta lian-ubuntu-beta lian3

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

Specifically System->Administration->Networking Unlock Then Authenticate then In the Hosts Tab
highlight the " localhost" line
click properties
make it read
IP address:
Aliases : localhost

In the General Tab
Hostname: lian-ubuntu-beta
Domain Name: (nothing or blank)