Hello Fedora users, I don't get nsswitch to work as I am used to it on other Unices such as Solaris (ok, it has to work on the inventors' OS, hasn't it?) or HP-UX. The problem is that I need to register private (virtual) IP addresses that are neither routable nor resolvable by any DNS server (even our own), but whose bidirectional resolution is required by certain applications. This is usually no problem because it boils down to registering them in /etc/hosts, like in the old days. Because nowadays there is a multitude of name services (e.g. DNS, NIS, LDAP) one would have to configure the name service switch. But this is usually as simple as telling applications to use the local files before referring to any other name services. e.g. on an HP-UX box I would simply add these entries $ uname -srv HP-UX B.11.11 U $ tail -1 /etc/hosts 123.123.123.123 sample.our-rotten.org sample $ grep hosts /etc/nsswitch.conf hosts: files [NOTFOUND=continue] dns Now on HP-UX the getent tool lacks, but therefore they provide a tool called nsquery which is equally suited for testing the nsswitch. $ nsquery hosts sample Using "files [NOTFOUND=continue] dns" for the hosts policy. Searching /etc/hosts for sample Hostname: sample.our-rotten.org Aliases: sample Address: 123.123.123.123 Switch configuration: Terminates Search $ nsquery hosts 123.123.123.123 Using "files [NOTFOUND=continue] dns" for the hosts policy. Searching /etc/hosts for 123.123.123.123 Hostname: sample.our-rotten.org Aliases: sample Address: 123.123.123.123 Switch configuration: Terminates Search As can be seen resolution works bidirectional independent of what any nameserver may have to say (because it isn't even bothered) The nice thing on HP-UX is that they even patched their nslookup resolver tool to honour nsswitch.conf settings $ nslookup 123.123.123.123 Using /etc/hosts on: venice looking up FILES Name: sample.our-rotten.org Address: 123.123.123.123 Aliases: sample $ nslookup sample.our-rotten.org Using /etc/hosts on: venice looking up FILES Name: sample.our-rotten.org Address: 123.123.123.123 Aliases: sample So this is the functionality I expect from any modern Unix-(SysV)-like OS. However, so far I have never achieved this on Linux (or a RedHat based distro to be precise) I assume that I simply lack some lib or maybe a PAM patch. So doing the same on this Fedora 3 box I get $ uname -srv Linux 2.6.9-1.667smp #1 SMP Tue Nov 2 14:59:52 EST 2004 $ cat /etc/fedora-release Fedora Core release 3 (Heidelberg) $ grep ^hosts /etc/nsswitch.conf hosts: files [NOTFOUND=continue] dns $ tail -1 /etc/hosts 123.123.123.123 sample.our-rotten.org sample $ getent hosts sample 123.123.123.123 sample.our-rotten.org sample $ getent hosts 123.123.123.123 $ echo $? 2 Why isn't it doing reverse lookups? Needless to say that neither nslookup, nor host, nor dig care about the content of nsswitch.conf but instead straight away seem to query the first nameserver from /etc/resolv.conf. These are the DNS related RPMs installed on the box $ rpm -qa|grep -E dns\|bind bind-libs-9.2.4-2 ypbind-1.17.2-3 bind-utils-9.2.4-2 $ rpm -qf /etc/nsswitch.conf glibc-2.3.3-74 $ rpm -qf /etc/resolv.conf file /etc/resolv.conf is not owned by any package $ rpm -qf /etc/hosts file /etc/hosts is not owned by any package I consulted the RedHat Refernce Guide but the only reference to the nsswitch therein relates to LDAP. The rest is silence. Regards Ralph
