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man pages section 4: File Formats

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Updated: July 2017
 
 

ftpusers(4)

Name

ftpusers - file listing users to be disallowed ftp login privileges

Synopsis

/etc/ftpd/ftpusers

Description

The ftpusers file lists users for whom ftp login privileges are disallowed. Each ftpuser entry is a single line of the form:

name

where name is the user's login name.

The FTP Server, in.ftpd-1m, reads the ftpusers file. If the login name of the user matches one of the entries listed, it rejects the login attempt.

The ftpusers file has the following default configuration entries:


root
daemon
bin
sys
adm
lp
uccp
nuucp
dladm
smmsp
listen
gdm
upnp
xvm
mysql
openldap
webservd
svctag
unknown
nobody
noaccess
nobody4

These entries match the default instantiated entries from passwd(4). The list of default entries typically contains the superuser root and other administrative and system application identities.

The root entry is included in the ftpusers file as a security measure since the default policy is to disallow remote logins for this identity. This policy is also set in the default value of the CONSOLE entry in the /etc/default/login file. See login(1). If you allow root login privileges by deleting the root entry in ftpusers, you should also modify the security policy in /etc/default/login to reflect the site security policy for remote login access by root.

Other default entries are administrative identities that are typically assumed by system applications but never used for local or remote login, for example sys and nobody. Since these entries do not have a valid password field instantiated in shadow(4), no login can be performed.

If a site adds similar administrative or system application identities in passwd(4) and shadow(4), for example, majordomo, the site should consider including them in the ftpusers file for a consistent security policy.

Lines that begin with # are treated as comment lines and are ignored.

Files

/etc/ftpd/ftpusers

A file that lists users for whom ftp login privileges are disallowed by default.

/etc/ftpusers

This is symbolic link to /etc/ftpd/ftpusers.

/etc/default/login

Establishes login environment.

/etc/passwd

Password file.

/etc/shadow

Shadow password file.

Attributes

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE
ATTRIBUTE VALUE
Availability
service/network/ftp
Interface Stability
See below.

The Interface Stability for /etc/ftpd/ftpusers is Volatile.

See Also

login(1), passwd(4), shadow(4), attributes(5), environ(5)