X-Git-Url: https://git.decadent.org.uk/gitweb/?p=nfs-utils.git;a=blobdiff_plain;f=utils%2Fexportfs%2Fexports.man;h=c726dd995b5b4bdeec3515b1820c677bf482127c;hp=3d3d7f5047bf68e091b9877907eb57a0d17a7dd5;hb=c18e9a780f376b868e62b75abe64b0fd9915ada5;hpb=8c947a43b6eb4ae1ab0c034e6ba6e8ec035b3505 diff --git a/utils/exportfs/exports.man b/utils/exportfs/exports.man index 3d3d7f5..c726dd9 100644 --- a/utils/exportfs/exports.man +++ b/utils/exportfs/exports.man @@ -1,18 +1,22 @@ -.TH EXPORTS 5 "4 March 2005" "Linux" "Linux File Formats Manual" +.\"@(#)exports.5" +.\" +.TH exports 5 "31 December 2009" .SH NAME -exports \- NFS file systems being exported (for Kernel based NFS) -.SH SYNOPSIS -.B /etc/exports +exports \- NFS server export table .SH DESCRIPTION The file .I /etc/exports -serves as the access control list for file systems which may be -exported to NFS clients. It is used by -.IR exportfs (8) +contains a table of local physical file systems on an NFS server +that are accessible to NFS clients. +The contents of the file are maintained by the server's system +administrator. +.PP +Each file system in this table has a list of options and an +access control list. +The table is used by +.BR exportfs (8) to give information to -.IR mountd (8) -and to the kernel based NFS file server daemon -.IR nfsd (8). +.BR mountd (8). .PP The file format is similar to the SunOS .I exports @@ -34,7 +38,9 @@ double quotes. You can also specify spaces or other unusual character in the export name using a backslash followed by the character code as three octal digits. .PP -To apply changes to this file, run exportfs \-ra or restart the NFS server. +To apply changes to this file, run +.BR exportfs \-ra +or restart the NFS server. .PP .SS Machine Name Formats NFS clients may be specified in a number of ways: @@ -61,9 +67,10 @@ simultaneously. This is done by specifying an IP address and netmask pair as .IR address/netmask where the netmask can be specified in dotted-decimal format, or as a -contiguous mask length (for example, either `/255.255.252.0' or `/22' appended -to the network base address result in identical subnetworks with 10 bits of -host). Wildcard characters generally do not work on IP addresses, though they +contiguous mask length. +For example, either `/255.255.252.0' or `/22' appended +to the network base IPv4 address results in identical subnetworks with 10 bits of +host. Wildcard characters generally do not work on IP addresses, though they may work by accident when reverse DNS lookups fail. '''.TP '''.B =public @@ -106,7 +113,7 @@ preceding sec= option. The only options that are permitted to vary in this way are ro, rw, no_root_squash, root_squash, and all_squash. .PP .SS General Options -.IR exportfs +.BR exportfs understands the following export options: .TP .IR secure "\*d @@ -139,12 +146,13 @@ storage (see above). In releases of nfs-utils up to and including 1.0.0, this option was the -default. In all subsequence releases, +default. In all releases after 1.0.0, .I sync is the default, and .I async must be explicitly requested if needed. -To help make system administrators aware of this change, 'exportfs' +To help make system administrators aware of this change, +.B exportfs will issue a warning if neither .I sync nor @@ -188,7 +196,7 @@ The option is currently only effective on .I "single host exports. It does not work reliably with netgroup, subnet, or wildcard -exports. +exports. This option can be very useful in some situations, but it should be used with due care, and only after confirming that the client system @@ -246,7 +254,7 @@ If you genuinely require subtree checking, you should explicitly put that option in the .B exports file. If you put neither option, -.I exportfs +.B exportfs will warn you that the change is pending. .TP @@ -272,7 +280,9 @@ or .TP .IR no_acl On some specially patched kernels, and when exporting filesystems that -support ACLs, this option tells nfsd not to reveal ACLs to clients, so +support ACLs, this option tells +.B nfsd +not to reveal ACLs to clients, so they will see only a subset of actual permissions on the given file system. This option is safe for filesystems used by NFSv2 clients and old NFSv3 clients that perform access decisions locally. Current @@ -381,7 +391,7 @@ of the filesystem must be handled elsewhere.) .SS User ID Mapping .PP -.I nfsd +.B nfsd bases its access control to files on the server machine on the uid and gid provided in each NFS RPC request. The normal behavior a user would expect is that she can access her files on the server just as she would @@ -399,19 +409,19 @@ and can be turned off with .IR no_root_squash . .PP By default, -'''.I nfsd +'''.B nfsd '''tries to obtain the anonymous uid and gid by looking up user '''.I nobody '''in the password file at startup time. If it isn't found, a uid and gid -.I exportfs +.B exportfs chooses a uid and gid of 65534 for squashed access. These values can also be overridden by the .IR anonuid " and " anongid options. '''.PP -'''In addition to this, -'''.I nfsd +'''In addition to this, +'''.B nfsd '''lets you specify arbitrary uids and gids that should be mapped to user '''nobody as well. Finally, you can map all user requests to the @@ -424,7 +434,7 @@ Here's the complete list of mapping options: Map requests from uid/gid 0 to the anonymous uid/gid. Note that this does not apply to any other uids or gids that might be equally sensitive, such as user -.IR bin +.IR bin or group .IR staff . .TP @@ -434,7 +444,7 @@ Turn off root squashing. This option is mainly useful for diskless clients. .IR all_squash Map all uids and gids to the anonymous user. Useful for NFS-exported public FTP directories, news spool directories, etc. The opposite option -is +is .IR no_all_squash , which is the default setting. .TP @@ -456,7 +466,7 @@ is supposedly that of user joe). /projects proj*.local.domain(rw) /usr *.local.domain(ro) @trusted(rw) /home/joe pc001(rw,all_squash,anonuid=150,anongid=100) -/pub (ro,insecure,all_squash) +/pub *(ro,insecure,all_squash) /srv/www \-sync,rw server @trusted @external(ro) '''/pub/private (noaccess) .fi @@ -468,7 +478,7 @@ and netgroups (this is the entry `@trusted'). The fourth line shows the entry for the PC/NFS client discussed above. Line 5 exports the public FTP directory to every host in the world, executing all requests under the nobody account. The -.I insecure +.I insecure option in this entry also allows clients with NFS implementations that don't use a reserved port for NFS. The sixth line exports a directory read-write to the machine 'server' @@ -478,15 +488,15 @@ all three mounts with the `sync' option enabled. '''access to the private directory. '''.SH CAVEATS '''Unlike other NFS server implementations, this -'''.I nfsd +'''.B nfsd '''allows you to export both a directory and a subdirectory thereof to -'''the same host, for instance +'''the same host, for instance '''.IR /usr " and " /usr/X11R6 . '''In this case, the mount options of the most specific entry apply. For -'''instance, when a user on the client host accesses a file in +'''instance, when a user on the client host accesses a file in '''.IR /usr/X11R6 , -'''the mount options given in the -'''.I /usr/X11R6 +'''the mount options given in the +'''.I /usr/X11R6 '''entry apply. This is also true when the latter is a wildcard or netgroup '''entry. .SH FILES @@ -499,7 +509,15 @@ all three mounts with the `sync' option enabled. .BR showmount (8). '''.SH DIAGNOSTICS '''An error parsing the file is reported using syslogd(8) as level NOTICE from -'''a DAEMON whenever nfsd(8) or mountd(8) is started up. Any unknown +'''a DAEMON whenever +'''.BR nfsd (8) +'''or +'''.BR mountd (8) +'''is started up. Any unknown '''host is reported at that time, but often not all hosts are not yet known -'''to named(8) at boot time, thus as hosts are found they are reported -'''with the same syslogd(8) parameters. +'''to +'''.BR named (8) +'''at boot time, thus as hosts are found they are reported +'''with the same +'''.BR syslogd (8) +'''parameters.