9 *vtysh* provides a combined frontend to all FRR daemons in a single combined
10 session. It is enabled by default at build time, but can be disabled through
11 the :option:`--disable-vtysh` option to the configure script.
13 *vtysh* has a configuration file, :file:`vtysh.conf`. The location of that
14 file cannot be changed from |INSTALL_PREFIX_ETC| since it contains options
15 controlling authentication behavior. This file will also not be written by
16 configuration-save commands, it is intended to be updated manually by an
17 administrator with an external editor.
21 This also means the ``hostname`` and ``banner motd`` commands (which both do
22 have effect for vtysh) need to be manually updated in :file:`vtysh.conf`.
25 .. clicmd:: copy FILENAME running-config
27 Process and load a configuration file manually; each line in the
28 file is read and processed as if it were being typed (or piped) to
35 .. clicmd:: terminal monitor [DAEMON]
37 Receive and display log messages.
39 It is not currently possible to change the minimum message priority (fixed
40 to debug) or output formatting. These will likely be made configurable in
43 Log messages are received asynchronously and may be printed both during
44 command execution as well as while on the prompt. They are printed to
45 stderr, unlike regular CLI output which is printed to stdout. The intent is
46 that stdin/stdout might be driven by some script while log messages are
47 visible on stderr. If stdout and stderr are the same file, the prompt and
48 pending input will be cleared and reprinted appropriately.
52 If ``vtysh`` cannot keep up, some log messages may be lost. The daemons
53 do **not** wait for, get blocked by, or buffer messages for ``vtysh``.
59 *vtysh* can call an external paging program (e.g. *more* or *less*) to
60 paginate long output from commands. This feature used to be enabled by
61 default but is now controlled by the ``VTYSH_PAGER`` environment variable
62 and the :clicmd:`terminal paginate` command:
64 .. envvar:: VTYSH_PAGER
66 If set, the ``VTYSH_PAGER`` environment variable causes *vtysh* to pipe
67 output from commands through the given command. Note that this happens
68 regardless of the length of the output. As such, standard pager behavior
69 (particularly waiting at the end of output) tends to be annoying to the
70 user. Using ``less -EFX`` is recommended for a better user experience.
72 If this environment variable is unset, *vtysh* defaults to not using any
75 This variable should be set by the user according to their preferences,
76 in their :file:`~/.profile` file.
78 .. clicmd:: terminal paginate
80 Enables/disables vtysh output pagination. This command is intended to
81 be placed in :file:`vtysh.conf` to set a system-wide default. If this
82 is enabled but ``VTYSH_PAGER`` is not set, the system default pager
83 (likely ``more`` or ``/usr/bin/pager``) will be used.
86 Permissions and setup requirements
87 ==================================
89 *vtysh* connects to running daemons through Unix sockets located in
90 |INSTALL_PREFIX_STATE|. Running vtysh thus requires access to that directory,
91 plus membership in the |INSTALL_VTY_GROUP| group (which is the group that the
92 daemons will change ownership of their sockets to).
94 To restrict access to FRR configuration, make sure no unauthorized users are
95 members of the |INSTALL_VTY_GROUP| group.
99 VTYSH implements a CLI option ``-u, --user`` that disallows entering the
100 characters "en" on the command line, which ideally restricts access to
101 configuration commands. However, VTYSH was never designed to be a privilege
102 broker and is not built using secure coding practices. No guarantees of
103 security are provided for this option and under no circumstances should this
104 option be used to provide any semblance of security or read-only access to
107 PAM support (experimental)
108 --------------------------
110 vtysh has working (but rather useless) PAM support. It will perform an
111 "authenticate" PAM call using |PACKAGE_NAME| as service name. No other
112 (accounting, session, password change) calls will be performed by vtysh.
114 Users using vtysh still need to have appropriate access to the daemons' VTY
115 sockets, usually by being member of the |INSTALL_VTY_GROUP| group. If they
116 have this membership, PAM support is useless since they can connect to daemons
117 and issue commands using some other tool. Alternatively, the *vtysh* binary
118 could be made SGID (set group ID) to the |INSTALL_VTY_GROUP| group.
122 No security guarantees are made for this configuration.
125 .. clicmd:: username USERNAME nopassword
127 If PAM support is enabled at build-time, this command allows disabling the
128 use of PAM on a per-user basis. If vtysh finds that an user is trying to
129 use vtysh and a "nopassword" entry is found, no calls to PAM will be made
133 .. _integrated-configuration-mode:
135 Integrated configuration mode
136 =============================
138 Integrated configuration mode uses a single configuration file,
139 :file:`frr.conf`, for all daemons. This replaces the individual files like
140 :file:`zebra.conf` or :file:`bgpd.conf`.
142 :file:`frr.conf` is located in |INSTALL_PREFIX_ETC|. All daemons check for the
143 existence of this file at startup, and if it exists will not load their
144 individual configuration files. Instead, ``vtysh -b`` must be invoked to
145 process :file:`frr.conf` and apply its settings to the individual daemons.
149 *vtysh -b* must also be executed after restarting any daemon.
152 Configuration saving, file ownership and permissions
153 ----------------------------------------------------
155 The :file:`frr.conf` file is not written by any of the daemons; instead *vtysh*
156 contains the necessary logic to collect configuration from all of the daemons,
157 combine it and write it out.
161 Daemons must be running for *vtysh* to be able to collect their
162 configuration. Any configuration from non-running daemons is permanently
163 lost after doing a configuration save.
165 Since the *vtysh* command may be running as ordinary user on the system,
166 configuration writes will be tried through *watchfrr*, using the ``write
167 integrated`` command internally. Since *watchfrr* is running as superuser,
168 *vtysh* is able to ensure correct ownership and permissions on
171 If *watchfrr* is not running or the configuration write fails, *vtysh* will
172 attempt to directly write to the file. This is likely to fail if running as
173 unprivileged user; alternatively it may leave the file with incorrect owner or
176 Writing the configuration can be triggered directly by invoking *vtysh -w*.
177 This may be useful for scripting. Note this command should be run as either the
178 superuser or the FRR user.
180 We recommend you do not mix the use of the two types of files. Further, it is
181 better not to use the integrated :file:`frr.conf` file, as any syntax error in
182 it can lead to /all/ of your daemons being unable to start up. Per daemon files
183 are more robust as impact of errors in configuration are limited to the daemon
184 in whose file the error is made.
186 .. clicmd:: service integrated-vtysh-config
189 Control whether integrated :file:`frr.conf` file is written when
190 'write file' is issued.
192 These commands need to be placed in :file:`vtysh.conf` to have any effect.
193 Note that since :file:`vtysh.conf` is not written by FRR itself, they
194 therefore need to be manually placed in that file.
196 This command has 3 states:
199 service integrated-vtysh-config
200 *vtysh* will always write :file:`frr.conf`.
203 no service integrated-vtysh-config
204 *vtysh* will never write :file:`frr.conf`; instead it will ask
205 daemons to write their individual configuration files.
207 Neither option present (default)
208 *vtysh* will check whether :file:`frr.conf` exists. If it does,
209 configuration writes will update that file. Otherwise, writes are performed
210 through the individual daemons.
212 This command is primarily intended for packaging/distribution purposes, to
213 preset one of the two operating modes and ensure consistent operation across
216 .. clicmd:: write integrated
218 Unconditionally (regardless of ``service integrated-vtysh-config`` setting)
219 write out integrated :file:`frr.conf` file through *watchfrr*. If *watchfrr*
220 is not running, this command is unavailable.
224 Configuration changes made while some daemon is not running will be
225 invisible to that daemon. The daemon will start up with its saved
226 configuration (either in its individual configuration file, or in
227 :file:`frr.conf`). This is particularly troublesome for route-maps and
228 prefix lists, which would otherwise be synchronized between daemons.