Provided by: sfs-server_0.8-0+pre20060720.1-1.1_i386
sfs_hosts - Host to address mapping overriding DNS
All SFS client software uses DNS to locate server names. This is some‐
what different from typical network utilities, which, often depending
on a configuration file such as /etc/nsswitch.conf, can sometimes com‐
bine DNS with other techniques, such as scanning the file /etc/hosts or
querying NIS (YP) servers.
SFS relies exclusively on DNS for several reasons. First, the file
system is designed to provide a global namespace. Using /etc/hosts,
for example, it is common for a machine to have two names--for instance
hostname, and hostname.domain.com. However, were the same file system
to be available under two different self-certifying pathnames, several
things would go wrong: First, bookmarks to /sfs/@hostname,.../...
would only work on the local network. Even worse, it might be possible
to lose a file by accidentally copying it onto itself, e.g., from
/sfs/@hostname,.../... to /email@example.com,.../.... Finally,
SFS allows one to specify a TCP port number other than the default (4)
using DNS SRV records, while non-DNS mechanisms have no means of speci‐
fying port numbers.
Though DNS is fairly ubiquitous, there are situations in which one
might like to have ‘‘internal’’ connections to SFS servers routed dif‐
ferently from ‘‘external’’ ones. For example, when running SFS servers
behind a NAT box, external connections would need to be directed to the
external IP address of the NAT box, while it would be more efficient to
route internal connections directly to the internal IP address, without
going through the NAT. In such situations, often the best solution is
to set up a split DNS configuration. When split DNS is not an option,
however, the sfs_hosts mechanism will come in handy.
sfs_hosts is a superset of the standard /etc/hosts file format, that
additionally allows one to specify a port number by appending it with a
% character at the end of the address. By default, the port number is
4. For example, the following two lines both specify that
server.domain.com is running on port 4 of IP address 10.1.1.1:
If you really want /etc/hosts to override DNS with SFS, you can always
run ln -s ../hosts /etc/sfs/sfs_hosts, but this is not recommended.
Solutions involving DNS configuration will be much more scalable and
Host to address mapping overriding DNS
(Files in /etc/sfs supersede default versions in /usr/local/share/sfs.)
dirsearch(1), newaid(1), rex(1), sfsagent(1), sfskey(1), ssu(1),
sfs_config(5), sfs_srp_params(5), sfs_users(5), sfsauthd_config(5),
sfscd_config(5), sfsrosd_config(5), sfsrwsd_config(5), sfssd_config(5),
sfs_environ(7), funmount(8), nfsmounter(8), sfsauthd(8), sfscd(8), sfs‐
rosd(8), sfsrwcd(8), sfsrwsd(8), sfssd(8), vidb(8)
The full documentation for SFS is maintained as a Texinfo manual. If
the info and SFS programs are properly installed at your site, the com‐
mand info SFS should give you access to the complete manual.
For updates, documentation, and software distribution, please see the
SFS website at http://www.fs.net/.