And once again I was bitten by problems on my Debian laptop mounting directories from the file server via NFS. After a Debian dist-upgrade I couldn’t login to KDE any more. Shell login worked somehow but I quickly found out I could neither read nor write any files there. Apparently an “ls -al” showed me the right permissions (not just unmappable numeric UIDs or something of that kind) and an “id -a” confirmed that my LDAP PAM configuration still worked. But reading or writing any file just lead to “Permission denied”.
I’m not sure if it was an update in the nfs-common package in Sid. But I had the same problem before and it took me hours until I finally figured out that Debian’s NFS seems to use non-standard defaults. Namely the “sec” parameter when mounting the NFS share. According to the Solaris documentation the default is “sec=sys” which means that NFS uses the locally acquired UIDs and GIDs. Like /etc/passwd, NIS or LDAP/PAM. But on Debian it seems to default to “sec=krb5” or something. As I have close to no idea how to set up Kerberos and don’t want to (and talking to other people hardly anyone has used Kerberos either) I figured that it’s not really a sane default. I didn’t even ask for NFSv4 – just NFSv3. Perhaps I undeliberately set some /etc/default/nfs-common configuration setting wrong or whatever. It was just strange. So I set “sec=sys” in the options of the NFS share of my /etc/fstab and the problem was fixed.
Actually I wonder what network file systems other people use in a Debian environment. NFS somehow feels antiquated to me anyway.