The man page for exports(5) claims that remote accesses by root will be mapped to uid/gid -2:-2 unless overridden via the -maproot or -mapall options. But if root creates a file the result is clearly different:
# touch test # ls -alF total 32 drwxrwxrwx 2 ken 999 512 Apr 1 00:05 ./ drwxrwxr-x 12 root 999 512 Apr 1 00:05 ../ -rw-r--r-- 1 4294967294 999 0 Apr 1 00:07 test # The problem is obvious: despite the claims of the man page, there is no such uid/gid as -2:-2. This diff fixes the problem: Index: master.passwd =================================================================== RCS file: /cvs/src/etc/master.passwd,v retrieving revision 1.88 diff -u -p -r1.88 master.passwd --- master.passwd 5 Mar 2016 12:31:38 -0000 1.88 +++ master.passwd 1 Apr 2017 04:12:19 -0000 @@ -58,3 +58,4 @@ _tftp_proxy:*:108:108::0:0:tftp proxy da _ftp_proxy:*:109:109::0:0:ftp proxy daemon:/nonexistent:/sbin/nologin _sndiop:*:110:110::0:0:sndio privileged user:/var/empty:/sbin/nologin nobody:*:32767:32767::0:0:Unprivileged user:/nonexistent:/sbin/nologin +-2:*:4294967294:4294967294::0:0:Unprivileged NFS user:/nonexistent:/sbin/nologin Index: group =================================================================== RCS file: /cvs/src/etc/group,v retrieving revision 1.79 diff -u -p -r1.79 group --- group 5 Mar 2016 12:31:38 -0000 1.79 +++ group 1 Apr 2017 04:12:19 -0000 @@ -77,3 +77,4 @@ _sndiop:*:110: dialer:*:117: nogroup:*:32766: nobody:*:32767: +-2:*:4294967294: Happy April 1st! -ken