sfs_hosts(5)
NAME
sfs_hosts - Host to address mapping overriding DNS
DESCRIPTION
- All SFS client software uses DNS to locate server names.
- This is somewhat different from typical network utilities, which,
- often depending on a configuration file such as
- /etc/nsswitch.conf, can sometimes combine DNS with other tech
- niques, 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 ac
- cidentally copying it onto itself, e.g., from
- /sfs/@hostname,.../... to /sfs/@hostname.domain.com,.../.... Fi
- nally, 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 specifying port numbers.
- Though DNS is fairly ubiquitous, there are situations in
- which one might like to have ``internal'' connections to SFS
- servers routed differently 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 connec
- tions 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:
10.1.1.1 server.domain.com
10.1.1.1%4 server.domain.com- 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 flexible.
FILES
- /etc/sfs/sfs_hosts
/usr/local/share/sfs/sfs_hosts - Host to address mapping overriding DNS
- (Files in /etc/sfs supersede default versions in
- /usr/local/share/sfs.)
SEE ALSO
- 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), sfsrosd(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 command 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/.
AUTHOR
- sfsdev@redlab.lcs.mit.edu
- SFS 0.8pre 2006-07-20