7. Mount Checklist

This section is based on IBM Corp.s ``NFS mount problem checklist''. Many thanks to them for making it available for this HOWTO. If you experience a problem mounting a NFS filesystem please refer to this list before posting your problem. Each item describes a failure mode and the fix.

1. Mount keeps saying RPC: Program not registered

   Is the portmapper running?

   Fix: Start it.

   Is mountd running?

   Fix: Start it.

   Is nfsd running?

   Fix: Start it.

   Is the portmapper forbidden to answer by /etc/hosts.deny?

   Fix: Either remove the rule in hosts.deny or add a rule to hosts.allow such that the portmapper is allowed to talk to you.

2. File system not exported, or not exported to the client in question.

   Fix: Export it

3. Name resolution doesn't jibe with the exports list.

   e.g.: export list says export to johnmad but johnmad's name is resolved as johnmad.austin.ibm.com. mount permission is denied.

   Fix: Export to both forms of the name.

   It can also happen if the client has two interfaces with different names for each of the two and the export file only specifies one.

   Fix: export both interfaces.

   This can also happen if the server can't do a lookuphostbyname or lookuphostbyaddr (these are library functions) on the client. Make sure the client can do host <name>; host <ip_addr>; and that both shows the same machine.

   Fix: straighten out name resolution.

4. The file system was mounted after NFS was started (on that server). In that case the server is exporting underlying mount point, not the mounted filesystem.

   Fix: Shut down NFSd and then restart it.

   Note: The clients that had the underlying mount point mounted will get problems accessing it after the restart.

5. The date is wildly off on one or both machines (this can mess up make)

   Fix: Get the date set right.

   The HOWTO author recommends using NTP to synchronize clocks. Since there are export restrictions on NTP in the US you have to get NTP for Debian, Red Hat or Slackware from ftp://ftp.hacktic.nl/pub/replay/pub/linux or a mirror.

6. The server can not accept a mount from a user that is in more than 8 groups.

   Fix: decrease the number of groups the user is in or mount via a different user.