We’re experimenting with deploying SUSE 10 SP3 systems and adding them to a Windows domain and DNS. Oddly, when we register in DNS, it gets registered under two address: the real IP address, and the address 127.0.0.2. Also, an ip addr command shows that the loopback device lo has two addresses: 127.0.0.1 and 127.0.0.2.

The above behavior is just on SP3. On SUSE 10 SP2, the lo device has only the 127.0.0.1 address, and the system is able to register correctly in DNS.

Has anyone ever seen this behavior? Do you know what the 127.0.0.2 address signifies, or how to get rid of it?

Thanks, Joseph

I'm answering because nobody else has, not because I know much about it ...

127.x.x.x addresses are all local. Rarely is there any need to use more than one and 127.0.0.1 is conventional. Netsearching showed others used/created:

• By Yast (sorry -- can't find the URL now).
• For starting MySQL when no DNS system available
• a loopback device for a second NIC
• When using two DNS services on one system
• To give multiple names to the local system (not clear why they are not all given on 127.0.0.1 -- maybe it's a Novell/SUSE thing)
  
  Code:

  127.0.0.1 localhost localhost.localdomain
  127.0.0.2 myhost myhost.mydomain

• To resolve DHCP initialisation problems (I didn't understand clearly enough what these were about to be able to choose an illustrative URL -- my German is very basic)

What is the DNS system that the SUSE 10 SP3 systems are registering with?

1 members found this post helpful.

Thanks, Catkin. We're registering with a Windows 2008 DNS server. I finally got this to work after a friend suggested that I edit the /etc/sysconfig/network/ifcfg-lo file and delete the entry for 127.0.0.2. Then I did a service network restart and was able to do the dns register. This time the system registered with only the correct address.

After that I restored the 127.0.0.2 address to the ifcfg-lo file again and once more restarted the network service. So the 127.0.0.2 loopback is still available if some app needs it some day.

Regards, Joseph

Glad you found a workaround and hope you're OK with doing it each boot. If these are new servers I'd be tempted to leave the 127.0.0.2 address out and see if anything breaks or goes slowly; 127.0.0.2 might not actually be needed. If that works then you don't have to do the process each boot.

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