Defines default configuration information for the Dynamic Host Configuration Protocol (DHCP) server program (dhcpsd).
The dhcpsd configuration file contains entries for logging information, options to return, machines to configure, and other items.
Following are the formats for the data in the configuration file.
Code | Name | Data Field Format and Notes |
0 | Pad Option | No need to specify |
255 | End Option | No need to specify |
1 | Subnet Mask | Unsigned Long |
2 | Time Offset | Long |
3 | Router Option | IP Addresses |
4 | Timer Server Option | IP Addresses |
5 | Name Server Option | IP Addresses |
6 | Domain Name Server Option | IP Addresses |
7 | Log Server Option | IP Addresses |
8 | Cookie Server Option | IP Addresses |
9 | LPR Server Option | IP Addresses |
10 | Impress Server Option | IP Addresses |
11 | Resource Location Server Option | IP Addresses |
12 | Host Name Option | String |
13 | Boot File Size Option | Unsigned Short |
14 | Merit Dump File | String |
15 | Domain Name | String |
16 | Swap Server | IP Address |
17 | Root Path | String |
18 | Extensions Path | String |
Code | Name | Data Field Format and Notes |
19 | IP Forwarding Enable/Disable Option | Boolean |
20 | Non-local Source Routing Enable/Disable Option | Boolean |
21 | Policy Filter Option | IP Address Pairs |
22 | Maximum Datagram Reassembly Size | Unsigned Short |
23 | Default IP Time-to-live | Unsigned Byte |
24 | Path MTU Aging Timeout Option | Unsigned Long |
25 | Path MTU Plateau Table | Unsigned Shorts |
Code | Name | Data Field Format and Notes |
26 | Interface MTU Option | Unsigned Short |
27 | All Subnets are Local Option | Boolean |
28 | Broadcast Address Option | IP Address |
29 | Perform Mask Discovery Option | Boolean |
30 | Mask Supplier Option | Boolean |
31 | Perform Router Discovery Option | Boolean |
32 | Router Solicitation Address Option | IP Address |
33 | Static Route Option | IP Address Pairs |
Code | Name | Data Field Format and Notes |
34 | Trailer Encapsulation Option | Boolean |
35 | ARP Cache Timeout Option | Unsigned Long |
36 | Ethernet Encapsulation Option | Boolean |
Code | Name | Data Field Format and Notes |
37 | TCP Default TTL Option | Unsigned Byte |
38 | TCP Keepalive Interval Option | Unsigned Long |
39 | TCP Keepalive Garbage Option | Boolean |
Code | Name | Data Field Format and Notes |
40 | NIS Domain Option | String |
41 | NIS Option | IP Addresses |
42 | Network Time Protocol Servers Option | IP Addresses |
43 | Vendor Specific Information | Unsigned Bytes |
44 | NetBIOS over TCP/IP Name Server Option | IP Addresses |
45 | NetBIOS over TCP/IP Datagram Distribution Server | IP Addresses |
46 | NetBIOS over TCP/IP Node Type Option | Unsigned Byte |
47 | NetBIOS over TCP/IP Scope Option | Unsigned Bytes |
48 | X Window System Font Server Option | IP Addresses |
49 | X Window System Display Manager Option | IP Addresses |
Code | Name | Data Field Format and Notes |
50 | Request IP Address | No need to specify |
51 | IP Address Lease Time | Unsigned Long |
52 | Option Overload | No need to specify |
53 | DHCP Message Type | No need to specify |
54 | Server Identifier | No need to specify |
55 | Parameter Request List | No need to specify |
56 | Message | String |
57 | Maximum DHCP Message Size | No need to specify |
58 | Renewal (T1) Time Value | No need to specify |
59 | Rebinding (T2) Time Value | No need to specify |
60 | Class Identifier of Client | Generated by client |
61 | Client Identifier | Generated by client |
Code | Name | Data Field Format and Notes |
sa | Server Address for the BOOTP client to use | IP Address |
bf | Bootfile for the BOOTP client to use | String |
hd | Home Directory for the BOOTP client to search for the bootfile | String |
Following is an example of BOOTP specific options:
option sa 1.1.2.2 option hd "/vikings/native" option bf "bootfile.asdg"
Other option numbers may be specified, up to a maximum of 255. The options not listed above must be specified with the unsigned byte list type. Following is an example:
option 178 01 34 53 # Means place tag 178 with value 0x013553
leaseTimeDefault <amount>[<unit>] | |
Specifies the default lease
duration for the leases issued by this server. In the absence of any more specific lease duration (for
example, lease duration for specific client(s) or class of clients), the lease duration specified by this
parameter takes effect.
The amount is specified by a decimal number. The unit is one of the following (plural is accepted):
There is at least one white space in between the amount and unit. Only the first amount following the keyword has effect. If this parameter is not specified, the default lease duration is one (1) hour. This parameter should appear outside of any pair of curly braces, for example, it applies to all leases issued by this server. Note: This keyword only applies to the default for all addresses. To specify a specific lease time for a subnet, network, class or client, use the usual "option 51 value" to specify that lease time (in seconds). | |
leaseExpireInterval <amount> [<unit>] | |
Specifies the time interval at which the lease expiration condition is examined, and if a running lease
meets such condition, it is expired. The value of this parameter applies to all leases administered
by this server.
The amount is specified by a decimal number. The unit is one of the following (plural is accepted):
There is at least one white space in between the amount and unit. Only the first amount following the keyword has effect. If this parameter is not specified, the default interval is one (1) minute. This parameter should appear outside of any pair of curly braces, for example it applies to all leases issued by this server. The value of this parameter should be in proportion with that of parameter leaseTimeDefault so that the expirations of leases are recognized in time. | |
supportBOOTP [yes | no] | |
Indicates to the server whether or not to support requests from BOOTP clients.
If yes is specified, the server will support BOOTP clients. If the value field is not a yes , or the keyword is omitted, the server will not support BOOTP clients. The scope of this parameter covers all the networks and subnets administered by this server. If the server previously supported BOOTP clients and has been reconfigured not to support BOOTP clients, the address binding for a BOOTP client established before the reconfiguration, if any, will still be maintained until the time when that BOOTP client sends a request again (when it is rebooting.) At that time, the server will not respond, and the binding will be removed. | |
supportunlistedClients [yes | no] | |
Indicates to the server whether or not to support requests from clients that are
not specifically configured with their own individual client statements in the server.
If yes is specified, the server will support unlisted clients. If the value field is anything other than yes , the server will not support unlisted clients. If this keyword is not found in the file, the server will support clients not specifically configured with a client statement. | |
updateDNS <string> | |
A string enclosed in quotes, indicating a program to execute to update the DNS
server with the new inverse mapping for the IP address and names served by dhcp. This
string should include four %s's to indicate the placement of the following information from
the dhcp client:
These values are output by dhcp in this order: hostname domainname Ip Address leasetime A script /usr/sbin/dhcpaction has been provided with this function, as well as actions to help NIM interact with DHCP clients. Run the script as follows: /usr/sbin/dhcpaction hostname domainname ipaddress leasetime < A | PTR | BOTH | NONE > < NONIM | NIM > The first four parameters are what will be used to update the DNS server. The fifth parameter tells dhcpaction to update the A record, the PTR record, or both, or none. The options are A, PTR, BOTH, NONE. The sixth parameter is used to tell servers that NIM is being used, and processing needs to be done when a client changes address. The options for this are NIM and NONIM. An example follows: updateDNS "/usr/sbin/dhcpaction %s %s %s %s PTR NONIM 2>&1 >>/tmp/updns.out" |
We are also setting up two global options that should apply to all clients we serve. We are saying that there is a printer at 10.11.12.13 for everyone to use and the global domain name is dreampark . We are defining one network that has subnetting on the first 24 bits.
Thus, the network we are defining has some number of subnets and all the subnets we are specifying in this network scope have netmask of 255.255.255.0. Under that network, we are defining some options for that network and some subnets. The subnets define the actual addresses available for distribution. There are two subnets. Inside the second subnet, there is a class. The class information only applies to hosts on the second subnet that request that class. If that class is asked for the host, it will get two netbios options. If the address is in the first subnet, it will get the options in the subnet clause, which are nothing. If the host is in the second subnet, it will get all the options in the clause for the second subnet. If it also has the class, it will get the class options. If options are repeated with the same scope or a sub-scope, these options are concatenated together and set as one option. All hosts given an address from one of the two subnets will receive the options that are in the network scope.
leaseTimeDefault 30 minutes leaseExpireInterval 3 minutes supportBOOTP yes supportUnlistedClients yes option 9 10.11.12.13 # printer for all option 15 dreampark # domain name network 9.0.0.0 24 { subnet 9.2.218.0 9.2.218.1-9.2.218.128 subnet 9.67.112.0 9.67.112.1-9.67.112.64 { option 28 9.67.112.127 # broadcast address option 9 9.67.112.1 # printer 1 option 9 9.67.112.2 # printer 2 option 15 sandbox. # domain name class netbios_host { #Netbi ov tcp/ip name server option 44 9.67.112.125 Netbi over tcp/ip node type option 46 2 } } option 15 toyland # domain name option 9 9.68.111.128 # printer 3 option 33 1.2.3.4:9.8.7.1 # route to the moon option 33 5.6.7.8:9.8.7.2 # route to the mars # routes to black holes option 3 11.22.33.44 55.66.77.88 }
The DHCP server Greg is responsible for network 9.3.145.0, subnet mask 255.255.255.192. The DHCP server Fred is responsible for network 9.3.146.128, subnet mask 255.255.255.240. Each server provides its own domain name. Other options named and unnamed may be placed in the server's configuration section.
Note: This format is used by dhcpsconf, which generateS the appropriate configuration files for DHCP servers Greg and Fred .
# Named resources Section ## "Network 1 Subnet Netmask" "option 1 255.255.255.192" ## "Network 2 Subnet Netmask" "option 1 255.255.255.240" ## "Network 1 Domain Name" "option 15 "bizarro.austin.ibm.com"" ## "Network 2 Domain Name" "option 15 "superman.austin.ibm.com"" ## "Network 1 Network" "network 9.3.145.0 26" ## "Network 2 Network" "network 9.3.146.128 27" ### "DHCP Server Greg" "logItem SYSERR" ### "DHCP Server Greg" "numlogfiles 6" ### "DHCP Server Greg" "logfilesize 100" ### "DHCP Server Greg" "logfilename /usr/tmp/dhcpgreg.log" ### "DHCP Server Greg" "network 9.3.145.0 26" ### "DHCP Server Greg" "{" ### "DHCP Server Greg" "option 15 "bizarro.austin.ibm.com"" ### "DHCP Server Greg" "}" ### "DHCP Server Fred" "logItem SYSERR" ### "DHCP Server Fred" "logItem OBJERR" ### "DHCP Server Fred" "numlogfiles 3" ### "DHCP Server Fred" "logfilesize 50" ### "DHCP Server Fred" "logfilename /usr/tmp/dhcpfred.log" ### "DHCP Server Fred" "network 9.3.146.128 27" ### "DHCP Server Fred" "{" ### "DHCP Server Fred" "option 15 "superman.austin.ibm.com"" ### "DHCP Server Fred" "}"
This file is part of TCP/IP in Network Support Facilities in Base Operating System (BOS) Runtime.
The dhcpsd daemon, the dhcpsconf command
The DHCP Client Configuration File
TCP/IP Address and Parameter Assignment - Dynamic Host Configuration Protocol (DHCP) in AIX Version 4.3 System Management Guide: Communications and Networks.
Problems with Dynamic Host Configuration Protocol (DHCP) in AIX Version 4.3 System Management Guide: Communications and Networks.