How do I work disconnected from the network, for example with a notebook?

If a Linux PC (RH 6.2) is configured to use a DNS, but is temporarily disconnected from the network, it does not behave properly. In this situation, none of the configured DNS is available (assuming there is no a local DNS) and:

• rsh seems not to work any more (i.e. the command 'rsh lap003469vm ls' hangs)
• CORBA seems not to work (i.e. 'Activate Activator' hanged on CORBA::ORB_init())

Actually, they do not hang forever, but just for about 15 minutes, then they go on and work fine. The solution (or better the workaround) is to edit /etc/nsswitch.conf and, when disconnected from the network, remove from the line:

  hosts: files dns

the 'dns' option, so that it looks:

  hosts: files

The line 'hosts: files dns' should mean that when (reverse-)resolving names, the resolver should look first in /etc/hosts then in the DNS. Nevertheless, in our case it seems to look anyway first in the DNS'es. If you remove the 'dns' option, it looks only in /etc/hosts and it works immediately, but you have to remember to change again the /etc/nsswitch.conf file if you want to use the DNS again.

-- DavidFugate - 28 Jun 2005