Handling domain name server lookups from the hosts on the LAN with IP masquerading has always presented a problem. There are two ways of accomodating DNS in a masquerade environment. You can tell each of the hosts that they use the same DNS that the Linux router machine does, and let IP masquerade do its magic on their DNS requests. Alternatively, you can run a caching name server on the Linux machine and have each of the hosts on the LAN use the Linux machine as their DNS. Although a more aggressive action, this is probably the better option because it reduces the volume of DNS traffic travelling on the Internet link and will be marginally faster for most requests, since they’ll be served from the cache. The downside to this configuration is that it is more complex. Section 6.3.4,” in Chapter 6, describes how to configure a caching name server.