| 35.3. DHCP Server Mode | ||
|---|---|---|
 | Chapter 35. DHCP - Dynamic Host Configuration Protocol |  |
| 35.3. DHCP Server Mode | ||
|---|---|---|
| | Chapter 35. DHCP - Dynamic Host Configuration Protocol | |
A DHCP server is an Internet host that returns configuration parameters to DHCP clients.
[09:56:36] ABILIS_CPX:s dhcplan:1 mode:server COMMAND EXECUTED [09:56:45] ABILIS_CPX:d dhcp lan:1- Not Saved (SAVE CONF), Not Refreshed (INIT) --------------------------------- Parameter: | Value: -------------+----------------------------------------------------------------- LAN: 1 NAME: NET: 192.168.029.000/24 MASK: 255.255.255.000 MAC-FILTER: # MODE: SERVER POOL1: 192.168.029.008:192.168.029.130 POOL2: # POOL3: # POOL4: # POOL5: # PROF: 1 DEF-LEASE: 36000 MAX-LEASE: 36000 ARPCHK: YES -------------------------------------------------------------------------------
![[Caution]](../images/caution.png) | Caution |
|---|---|
To activate the changes made on the lowercase parameters a save conf and an Abilis restart are required (i.e. With warm start command). |
The configuration of DHCP server mode is based on three tables:
DHCP Profiles table: table containing all the parameters to be distributed to clients (i.e. IP Address, Gateway, WINS, DSN, Domain, etc.);
DHCP Subnets: table containing the network IP address of the DHCP subnet, the subnet mask, the pools of addresses to distribute and the “lease” time of the IP addresses;
DHCP Hosts: allows to define a static association between a specific MAC-ADDRESS of a client and an IP address.
![[Tip]](../images/tip.png) | Tip |
|---|---|
Interesting chapters: Section 83.24.2, “How to activate the DHCP in server mode”; Section 35.3.2, “Example of configuration of DHCP in Server mode”. |
The DHCP Profiles table can hold up to 129 definitions, indexed from 0 up to 128.
The user can arbitrarily add/delete the definitions from the index 1 to 128. The profile with index 0 can't be deleted because it's a default profile.
Changes made on the table can be activated by executing the initialization command init res:dhcp.
The commands for the DHCP Profiles table management are:
d dhcp prof:xxx[,yyy,...] : display DHCP profile;
a dhcp prof:xxx [par:val] : add DHCP profile;
c dhcp prof:xxx[,yyy,...] :clears DHCP profile;
s dhcp prof:xxx[,yyy,...] par:val [par:val]: set DHCP profile parameters.
A complete list of available configuration parameters is available by typing d dhcp prof: ?.
[09:24:57] ABILIS_CPX:d dhcp prof: ?
D DHCP PROF:xxx[,yyy,...] Display DHCP profile [0..128, A]
DHCP Profile parameter(s):
NAME: Profile name.
Max 32 ASCII characters. Space not allowed.
TTL: IP time-to-live [0, 1..255]
KEEPALIVE: TCP keepalive interval [0, 15..65535 s]
NB-SCOPE-ID: Netbios scope identifier.
Max 32 ASCII characters. Space not allowed.
NB-NODE-TYPE: Netbios node type [UNK, B, P, M, H]
DOMAIN: IP domain name.
Max 32 ASCII characters. Space not allowed.
GW1: First gateway [# or 0.0.0.0, 1-126.x.x.x, 127.0.0.1, 128-223.x.x.x]
or IP resource [Ip-1..Ip-250]
GW2: Second (backup) gateway [# or 0.0.0.0, 1-126.x.x.x, 127.0.0.1,
128-223.x.x.x] or IP resource [Ip-1..Ip-250]
GW3: Third (backup) gateway [# or 0.0.0.0, 1-126.x.x.x, 127.0.0.1,
128-223.x.x.x] or IP resource [Ip-1..Ip-250]
DNS1: Primary Domain Name server [# or 0.0.0.0, 1-126.x.x.x, 127.0.0.1,
128-223.x.x.x] or IP resource [Ip-1..Ip-250]
DNS2: Secondary Domain Name server [# or 0.0.0.0, 1-126.x.x.x, 127.0.0.1,
128-223.x.x.x] or IP resource [Ip-1..Ip-250]
SMTP: Simple Mail Transport Protocol (SMTP) server [# or 0.0.0.0,
1-126.x.x.x, 127.0.0.1, 128-223.x.x.x] or IP resource [Ip-1..Ip-250]
POP3: Post Office Protocol (POP3) server [# or 0.0.0.0, 1-126.x.x.x,
127.0.0.1, 128-223.x.x.x] or IP resource [Ip-1..Ip-250]
NNTP: Network News Transport Protocol (NNTP) server [# or 0.0.0.0,
1-126.x.x.x, 127.0.0.1, 128-223.x.x.x] or IP resource [Ip-1..Ip-250]
WWW: World Wide Web (WWW) server [# or 0.0.0.0, 1-126.x.x.x, 127.0.0.1,
128-223.x.x.x] or IP resource [Ip-1..Ip-250]
FINGER: Finger server [# or 0.0.0.0, 1-126.x.x.x, 127.0.0.1, 128-223.x.x.x]
or IP resource [Ip-1..Ip-250]
IRC: Internet Relay Chat server [# or 0.0.0.0, 1-126.x.x.x, 127.0.0.1,
128-223.x.x.x] or IP resource [Ip-1..Ip-250]
NTP: NTP/SNTP server [# or 0.0.0.0, 1-126.x.x.x, 127.0.0.1,
128-223.x.x.x] or IP resource [Ip-1..Ip-250]
TIME: TIME server [# or 0.0.0.0, 1-126.x.x.x, 127.0.0.1, 128-223.x.x.x]
or IP resource [Ip-1..Ip-250]
WINS1: First WINS server [# or 0.0.0.0, 1-126.x.x.x, 127.0.0.1,
128-223.x.x.x] or IP resource [Ip-1..Ip-250]
WINS2: Second WINS server [# or 0.0.0.0, 1-126.x.x.x, 127.0.0.1,
128-223.x.x.x] or IP resource [Ip-1..Ip-250]
TFTP: TFTP server name.
Max 64 ASCII characters. Space not allowed.
BOOTFILE: Bootfile name.
Max 128 ASCII characters. Space not allowed.The DHCP Subnets table can hold up to 128 definitions.
Changes made on the table can be activated by executing the initialization command init res:dhcp.
The commands for the DHCP Subnets table management are:
d dhcp lan:xxx[,yyy,...] : display DHCP subnet;
a dhcp lan:xxx [par:val] : add DHCP subnet;
c dhcp lan:xxx[,yyy,...] :clears DHCP subnet;
s dhcp lan:xxx[,yyy,...] par:val [par:val]: set DHCP subnet parameters.
A complete list of available configuration parameters is available by typing d dhcp lan: ?.
[09:27:06] ABILIS_CPX:d dhcp lan:1
Parameter: | Value:
-------------+-----------------------------------------------------------------
LAN: 1
NAME:
NET: 192.168.029.000/24
MASK: 255.255.255.000
MAC-FILTER: #
MODE: SERVER
POOL1: 192.168.029.008:192.168.029.130
POOL2: #
POOL3: #
POOL4: #
POOL5: #
PROF: 1
DEF-LEASE: 36000
MAX-LEASE: 36000
ARPCHK: YES
-------------------------------------------------------------------------------The most important parameters:
MODESelect SERVER or RELAY service for this lan
[SERVER, RELAY].
NETNetwork address in DDN or network address and mask in Slash Notation [0.0.0.0, 1-126.x.x.x, 127.0.0.1, 128-223.x.x.x]/[0..32] or IP resource [Ip-1..Ip-999].
MASKNetwork mask in DDN [0.0.0.0, 128.0.0.0-255.255.255.252]. <Only if NET: is not equal to an IP resource>
MAC-FILTEREnables/disables the selection of serviceable clients
based on their MAC address. When it is set to
YES, MAC filtering is enabled. When DHCP
receives an incoming request and before processing it, the DHCP
verifies that the sender's MAC address is allowed by using
MAC-LIST and MAC-RULE
parameters current setting (MAC-LIST and
MAC-RULE appear when
MAC-FILTER is set to
YES).
Parameters for mode:RELAY
only:
SERVERDHCP Server to which requests must be forwarded: IP address or IP list name [#, ListName, 1-126.x.x.x, 127.0.0.1, 128-223.x.x.x].
MAX-HOPSMaximum allowed DHCP Relay Agent hops in forwarded requests [1..16].
LOCIPADDSource IP address used for the requests relayed to the server(s) [R-ID, OUT-IP, 1-126.x.x.x, 127.0.0.1, 128-223.x.x.x].
Parameters for mode:SERVER
only:
POOL1..5Enables ICMP checking of IP address. When it is set to
YES, ICMP checking is enabled. Before sending
the DHCPOFFER message, the server sends two ICMP ping requests
to check the IP address which was allocated. If both timeouts
expire, the server will send the DHCP offer message, otherwise
it will mark this IP address as abandoned and will not send
response.
PROFProfile [NONE, 1..128].
DEF-LEASEDefault lease time of the IP address [60..1000000 s]
MAX-LEASEMaximum lease time of the IP address [60..1000000 s]
ARPCHKEnable/disable ARP check before assigning an IP address
[NO, YES]. When it is set to YES, ARP
checking is enabled. Before sending the DHCPOFFER message, the
server sends two ARP requests to check the IP address which was
allocated. If both timeouts expire, the server will send the
DHCP offer message, otherwise it will mark this IP address as
abandoned and will not send response.
The DHCP Hosts table can hold up to 500 definitions, indexed from 1 up to 500.
Changes made on the table can be activated by executing the initialization command init res:dhcp.
The commands for the DHCP Hosts table management are:
d dhcp host:xxx[,yyy,...] : display DHCP host;
a dhcp host:xxx [par:val] : add DHCP host;
c dhcp host:xxx[,yyy,...] :clears DHCP host;
s dhcp host:xxx[,yyy,...] par:val [par:val]: set DHCP host parameters.
A complete list of available configuration parameters is available by typing d dhcp host: ?
[09:27:33] ABILIS_CPX:d dhcp host: ?
D DHCP HOST:xx Display DHCP host [1..500, A]
DHCP Host parameter(s):
MAC: MAC address [00-00-00-00-00-01..FF-FF-FF-FF-FF-FF]
IP: IP address [0.0.0.0, 1-126.x.x.x, 127.0.0.1, 128-223.x.x.x]
PROF: Profile [LAN, 1..128]
NAME: Host name. From 0 up to 32 ASCII characters.
Spaces are not allowed. Case is preserved.In this example the DHCP Server is configured to distribute the following parameters:
Network address: 192.168.0.0/24
IP pool of addresses: from 192.168.0.131 to 192.168.0.179
DNS server 1:192.168.0.232
DNS server 2:192.168.0.251
Default Gateway: 192.168.0.232
WINS server: 192.168.0.50
SMTP server: 192.168.0.250
POP3 server: 192.168.0.250
No static association between MAC-ADDRESS and any leased IP
ICMP checking of IP address
No MAC Filtering
First, set the DHCP resource active.
[15:20:37] ABILIS_CPX:s p dhcp act:yesCOMMAND EXECUTED [15:40:56] ABILIS_CPX:d p dhcpRES:Dhcp - Not Saved (SAVE CONF), Not Refreshed (INIT) ------------------------ ------------------------------------------------------------------------ DESCR:Dynamic_Host_Configuration_Protocol LOG:DS ACT:YES srv-udp-locport:67 cli-udp-locport:68 msg-len:1472 TOS:0-N WDIR:C:\APP\DHCP\ - Server --------------------------------------------------------------- max-clients:300
Configure the DHCP Profiles table.
[15:54:54] ABILIS_CPX:a dhcp prof:1 name:Private_LAN gw1:192.168.0.232 dns1:192.168.0.232 dns2:192.168.0.251 smtp:192.168.0.250 pop3:192.168.0.250 wins1:192.168.0.50COMMAND EXECUTED [15:55:11] ABILIS_CPX:d dhcp prof- Not Saved (SAVE CONF), Not Refreshed (INIT) --------------------------------- PROF: |NAME: ------------------------------------------------------------------------------- 0 Default_profile 1 Private_LAN [15:55:27] ABILIS_CPX:d dhcp prof:1- Not Saved (SAVE CONF), Not Refreshed (INIT) --------------------------------- Parameter: | Value: -------------+----------------------------------------------------------------- PROF: 1 NAME: Private_LAN TTL: 0 KEEPALIVE: 0 NB-SCOPE-ID: NB-NODE-TYPE: UNK DOMAIN: GW1: 192.168.000.232 GW2: # GW3: # DNS1: 192.168.000.232 DNS2: 192.168.000.251 SMTP: 192.168.000.250 POP3: 192.168.000.250 NNTP: # WWW: # FINGER: # IRC: # NTP: # TIME: # WINS1: 192.168.000.050 WINS2: # TFTP: BOOTFILE: -------------------------------------------------------------------------------
Configure the DHCP Subnets table setting the network address, the pool and the identifier of DHCP Profile.
[16:02:17] ABILIS_CPX:a dhcp lan:1 mode:server name:Private_Lan net:192.168.0.0/24 pool1:192.168.0.131:192.168.0.179 prof:1COMMAND EXECUTED [16:03:22] ABILIS_CPX:d dhcp lan- Not Saved (SAVE CONF), Not Refreshed (INIT) --------------------------------- LAN: |NET: |MASK: ------------------------------------------------------------------------------- 1 192.168.000.000 255.255.255.000 [16:03:26] ABILIS_CPX:d dhcp lan:1- Not Saved (SAVE CONF), Not Refreshed (INIT) --------------------------------- Parameter: | Value: -------------+----------------------------------------------------------------- LAN: 1 NAME: Private_Lan NET: 192.168.000.000/24 MASK: 255.255.255.000 MAC-FILTER: # MODE: SERVER POOL1: 192.168.000.131:192.168.000.179 POOL2: # POOL3: # POOL4: # POOL5: # PROF: 1 DEF-LEASE: 36000 MAX-LEASE: 36000 ARPCHK: YES -------------------------------------------------------------------------------
Configuration of DHCP Hosts table isn't required.
Now the configuration is complete.
| Caution |
|---|---|
To initialize the resource, use command init res:dhcp (to set act the changes made on uppercase parameters and in the tables) and save the configuration with save conf command to make the changes permanent. |
| Caution |
|---|---|
To set act changes made on lowercase parameters a save conf and an Abilis restart are needed (i.e. With warm start command). |
| Tip |
|---|---|
Interesting chapters: Section 83.24.2, “How to activate the DHCP in server mode”. |
The DHCP bindings table is the memory database which stores bindings allocated for DHCP clients.
A binding record includes the information about the allocated IP address, the start time and the end time of lease, the profile which is currently used by a DHCP client and some other information.
The Table of DHCP bindings is used in server mode only.
| Tip |
|---|---|
Refer to Section 35.3.3.1, “Appendix - how DHCP bindings table works” to have more information about DHCP bindings tables functioning. |
Commands for handling DHCP bindings table are:
d dhcp bind: it displays DHCP bindings summary;
d dhcp binde: it display DHCP bindings detailst;
c dhcp bind: this command allows to remove a DHCP binding entry from the DHCP bindings table identified by the specified IP address.
Some examples follow.
[11:34:14] ABILIS_CPX:d dhcp bind------------------+----------------+------+-----------------+------------------ MAC: |IP: |PROF: |Last request(UTC)|Expiry on(UTC) ------------------+----------------+------+-----------------+------------------ A0-F3-C1-C8-5B-0B 192.168.020.050 1 04/06/2015 16:49 07/02/2036 06:28 20-C9-D0-96-05-A1 192.168.020.102 1 09/06/2015 06:30 09/06/2015 16:30 00-19-99-52-CB-A0 192.168.020.104 1 09/06/2015 05:09 09/06/2015 15:09 08-00-27-16-7D-01 192.168.020.107 1 09/06/2015 05:21 09/06/2015 15:21 C4-6E-1F-19-E0-4D 192.168.020.118 1 09/06/2015 07:01 09/06/2015 17:01 [11:34:21] ABILIS_CPX:d dhcp binde----+-----+-------------------+-----------------+-------+---------------------- O: | ST: | MAC: | IP: | PROF: | Last request(UTC) | Expiry on(UTC) ----+-----+-------------------+-----------------+-------+---------------------- H ACT A0-F3-C1-C8-5B-0B 192.168.020.050 1 04/06/2015 16:49:15 07/02/2036 06:28:15 ------------------------------------------------------------------------------- P INV 38-0B-40-C6-82-53 192.168.020.071 1 31/03/2015 13:33:41 31/03/2015 23:33:41 ------------------------------------------------------------------------------- P EXP 00-26-E8-7B-31-7F 192.168.020.100 1 01/06/2015 09:27:07 01/06/2015 19:27:07 ------------------------------------------------------------------------------- P EXP 34-31-11-DF-46-79 192.168.020.101 1 05/06/2015 08:21:55 05/06/2015 18:21:55 ------------------------------------------------------------------------------- P ACT 20-C9-D0-96-05-A1 192.168.020.102 1 09/06/2015 06:30:52 09/06/2015 16:30:52 ------------------------------------------------------------------------------- P EXP 18-20-32-A0-B7-3B 192.168.020.103 1 01/06/2015 09:27:12 01/06/2015 19:27:12 ------------------------------------------------------------------------------- P ACT 00-19-99-52-CB-A0 192.168.020.104 1 09/06/2015 05:09:09 09/06/2015 15:09:09 ------------------------------------------------------------------------------- P EXP 14-7D-C5-3B-CB-16 192.168.020.105 1 25/05/2015 11:42:53 25/05/2015 21:42:53 ------------------------------------------------------------------------------- P EXP 38-0B-40-C6-82-53 192.168.020.106 1 05/06/2015 08:23:37 05/06/2015 18:23:37 ------------------------------------------------------------------------------- P ACT 08-00-27-16-7D-01 192.168.020.107 1 09/06/2015 05:21:24 09/06/2015 15:21:24 ------------------------------------------------------------------------------- P EXP 00-0C-E7-A2-98-E2 192.168.020.108 1 08/06/2015 14:36:38 09/06/2015 00:36:38 ------------------------------------------------------------------------------- P EXP E4-D5-3D-84-ED-98 192.168.020.109 1 09/04/2015 12:05:28 09/04/2015 22:05:28 ------------------------------------------------------------------------------- P EXP 84-7A-88-B0-1A-A8 192.168.020.110 1 28/05/2015 07:25:08 28/05/2015 17:25:08 ------------------------------------------------------------------------------- P EXP 74-2F-68-76-1E-2B 192.168.020.111 1 21/05/2015 13:33:20 21/05/2015 23:33:20 ------------------------------------------------------------------------------- P EXP 5C-FF-35-2C-12-E2 192.168.020.112 1 21/05/2015 12:49:34 21/05/2015 22:49:34 ------------------------------------------------------------------------------- P REL C4-6E-1F-19-E0-E2 192.168.020.117 1 08/06/2015 09:04:36 08/06/2015 09:05:32 ------------------------------------------------------------------------------- P ACT C4-6E-1F-19-E0-4D 192.168.020.118 1 09/06/2015 07:01:23 09/06/2015 17:01:23 ------------------------------------------------------------------------------
Meaning of the most important parameters:
OOrigin of the binding [H: allocated from
host tables; P: allocated from IP pools of one
of subnets from subnets table;].
STState of the binding [REL: released;
ACT:active, EXP: expired,
AB: abandoned, INC:
incomplete, INV: invalid].
MACThe binded MAC address of the DHCP client.
IPThe IP address assigned to the DHCP client with the MAC address.
PROFThe identifier of DHCP profile from profiles table.
Last request(GMT)The GMT date and time value when the lease was assigned/renewed the last time.
Expiry on(GMT)The GMT date and time value when the lease will expire.
Here are few samples of bindings clear commands:
[15:00:45] ABILIS_CPX:c dhcp bind ip:192.168.0.161YOU ARE GOING TO DELETE THE SPECIFIED DHCP BINDING ENTRY FROM THE DATA BASE IN MEMORY. DO YOU WANT TO PROCEES (Y/N)?YCOMMAND EXECUTED
[15:00:45] ABILIS_CPX:c dhcp bind ip:aYOU ARE GOING TO DELETE THE WHOLE CONTENT OF THE DHCP BINDINGS DATA BASE IN MEMORY. DO YOU WANT TO PROCEES (Y/N)?YCOMMAND EXECUTED
DHCP bindings table is stored in the
DHCP.BND file in the location defined by the
WDIR parameter.
It allows storage of up to max-clients
bindings, one per each record.
Every one minute the DHCP server checks the bindings table and saves all bindings to the file, if the table was changed since the last time it was updated.
During Abilis CPX DHCP resource start-up, the DHCP driver executes the following operations:
If the file DHCP.BND exists:
Reads the bindings table from the CF;
Updates the file, making a write operation try;
Writing attempt successful: the DHCP server goes to the ACTIVE state;
Writing attempt unsuccessful: the DHCP server goes
to the STOP state; it writes a warning message into the
System Log (i.e. “W: DHCP STOPPED”) and it
doesn't load the bindings DHCP.BND
file content.
If the file doesn't exist:
It tries to create it. If it can't, the server goes to the STOP state and it writes a warning message into the System Log (i.e. “W: DHCP STOPPED”).
After loading the DHCP.BND file, the DHCP
server checks the bindings according to the current configuration of
the DHCP driver. The records which don't conform to the current
configuration will be marked as “not valid” and they will
not be used by the DHCP server.
The DHCP server makes the next checks when loading bindings and marks the binding as “invalid” in all the following cases:
The subnet record which is corresponding to the IP address from the binding isn't found in the subnets table.
The profile identifier from the binding isn't found in the profiles table.
If the binding is static (i.e. Allocated from the hosts):
The host record with the IP and MAC addresses which are corresponding to the IP and MAC addresses from the loading binding isn't found in the hosts table.
The IP address from the binding is found in one of the pools of the subnet record (i.e. If the corresponding subnet record was found).
if the binding is dynamic (i.e. Allocated from the pools):
The host record with the IP and MAC addresses which are corresponding to the IP and MAC addresses from the loading binding is found in the hosts table;
The IP address from the binding isn't found in one of the pools of the subnet record (i.e. If the corresponding subnet record was found).
| |  | |
| 35.2. DHCP Relay Mode |  | 35.4. DHCP diagnostics, statistics and debug |