3 .TH dhcpcd 8 "31 January 1998" "dhcpcd 1.3" "Linux System Manager's Manual"
6 dhcpcd \- DHCP client daemon
14 \%[\-c\ <ExecFilePath>]
16 \%[-i\ <vendorClassID>]
27 is an implementation of the DHCP client specified in
29 (when -r option is not specified) and
31 (when -r option is specified).
33 It gets the host information (IP address, netmask, broadcast address,
34 etc.) from a DHCP server and configures the network interface of the
35 machine on which it is running. It also tries to renew the lease time
49 syslog(LOG_DEBUG,...) messages for about every step it does.
50 It's recommended to use this option since it doesn't really
51 produce too much output but will greatly help in resolving
56 syslog facility for its output. To catch
58 debugging output add the following line to
62 local0.* /var/log/dhcpcd.log
64 and then refresh syslogd daemon:
66 kill -1 `cat /var/run/syslogd.pid`
74 process that is currently running. If
80 message to the server and destroy dhcpcd cache. In a case
84 which is normally used by
86 when rebooting the system
90 and will not destroy cache. When system boots
92 will use cache to request the same IP address
93 from DHCP server which was assigned before the
101 process that is currently running which
104 to try to renew the lease. If dhcpcd is not running, the flag
107 follows the normal startup procedure.
110 Makes dhcpcd RFC1541 (obsolete) compliant.
112 is RFC2131 compliant unless this option is specified.
115 Requests broadcast response from DHCP server.
118 Forces dhcpcd to calculate checksum on received packets.
123 to set domainname of the host to the domainname option
124 supplied by DHCP server.
129 to set hostname of the host to the hostname option supplied by DHCP server.
132 will NOT set hostname of the host to the hostname option
133 received from DHCP server.
135 .BI \-L \ <ConfigDir>
139 directory instead of default
141 to store configuration information.
146 to send second DHCP_DISCOVER message even
147 after receiving DHCP_OFFER on the first one. Some DHCP servers
148 expect the client to send second DHCP_DISCOVER message
149 before replying on DHCP_REQUEST.
154 from replacing existing
161 from replacing existing
163 file. Domainname is not updated unless \fB-D\fP is specified.
168 from replacing existing
175 goes through the DHCP negotiation sequence but
176 doesn't actually configure the interface. It does however
178 .I <ConfigDir>/dhcpcd-<interface>.info
180 .I <ConfigDir>/dhcpcd-<interface>.cache
181 files and it does attempt to execute
182 .I <ConfigDir>/dhcpcd.exe
183 script. The pathname of
185 executable script can
187 .I \-c \ <ExecFilePath>
190 option is used primarily for testing DHCP servers,
191 for obtaining multiple IP addresses for the same dummy interface, and/or
192 configuring virtual interfaces in conjunction with
199 Specifies (in seconds ) for how long
201 will try to get an IP address. The default is 60 seconds.
203 will not fork into background until it gets a valid IP address
204 in which case dhcpcd will return 0 to the parent process.
207 times out before receiving a valid IP address from DHCP server
209 will return exit code 1 to the parent process.
211 .BI \-c \ <ExecFilePath>
215 script instead of default
216 .I <ConfigDir>/dhcpcd.exe
217 script every time it configures or brings down the interface. See the
225 specifies a string used for the hostname option field when
227 sends DHCP messages. Some DHCP servers, notably those used by
228 @Home Networks, require the hostname option
229 field containing a specific string in the DHCP messages from clients.
231 .BI \-i \ <vendorClassID>
232 Specifies the vendor class identifier string.
234 uses the default vendor class identifier string (system name, system release,
235 and machine type) if it is not specified.
238 Specifies the client identifier string.
240 uses the default client identifier (MAC address of the network
241 interface) if it is not specified.
243 .BI \-l \ <leasetime>
244 Specifies (in seconds) the recommended lease time to the server. (Note
245 that the server can override this value if it sees fit). This value is
248 message. The default is infinite (0xffffffff).
251 Sends DHCP_INFORM message to DHCP server using ipaddr.
252 The optional ipaddr parameter must be in
253 the form xxx.xxx.xxx.xxx.
254 If no ipaddr parameter is given on the command line
256 will use the IP address currently assigned to the interface.
257 If there is no IP address currently assigned
260 will use previously obtained IP address stored in
261 .I <ConfigDir>/dhcpcd-<interface>.cache
267 from installing default routes provided by DHCP server.
268 If optional gateway ip address parameter
269 is supplied then use it for default route.
271 .BI \-w \ <windowsize>
272 Specifies the window size for the gateway route. Default = 32768.
275 Specifies the network interface name (eth0, eth1, etc.).
277 uses the network interface
279 unless an explicit name is specified.
287 directory used for storing files
295 .BI <ConfigDir>/dhcpcd-<interface>.info
298 saves the host information. The word
300 is actually replaced with the network interface name like
302 to which dhcpcd is attached.
304 .BI <ConfigDir>/dhcpcd.exe
307 will try to execute whenever it configures or brings down the interface. The
308 path to this executable script can be changed with
309 .I \-c \ <ExecFilePath>
312 passes 3 parameters to
316 .I dhcpcd.exe <HostInfoFilePath> <up|down|new> [-d]
318 .I <HostInfoFilePath>
320 .I dhcpcd-<interface>.info
323 is actually replaced with interface name dhcpcd is
324 attached to, e.g. "eth0". The second parameter values
326 mean the interface has been brought up with the same IP address as before ("up"), or
327 with the new IP address ("new"), or the interface has been brought down ("down"). Parameter
331 has been started with
335 .BI <ConfigDir>/dhcpcd-<interface>.cache
336 Cache file containing the previously assigned IP address and
340 is actually replaced with the network interface name like
349 when the client receives DNS and domain name options.
353 .B /etc/resolv.conf.sv
354 and will be restored back when
356 exits for any reason.
361 when the client receives NIS options.
366 and is restored back when
368 exits for any reason.
373 when the client receives NTP options.
378 and is restored back when
380 exits for any reason.
382 .BI <ConfigDir>/dhcpcd-<interface>.pid
383 file containing the process id of
387 is actually replaced with the network interface name like
394 .I Dynamic Host Configuration Protocol,
395 RFC2131 and RFC1541 (obsolete)
396 .I DHCP Options and BOOTP Vendor Extensions,
404 to calculate the lease expiration time. If the system time is changed
405 while the client is running, the lease expiration time may not be
411 Yoichi Hariguchi <yoichi@fore.com>
415 Sergei Viznyuk <sv@phystech.com>