A FastIron device configured as a
DHCP server can support up to 3000 DHCP clients.
Where a
FastIron device is configured as a DHCP server, you can configure DHCP options. These options
are passed to the connected DHCP clients and allow configuration of parameters such
as default router, host name, and domain name server.
The list of supported DHCP options that are
configured using option number is shown in the following table:
The following option numbers must be configured
using the option number: 80 through 84, 90, 95, 96, 99 through 111, 115 through
117, 126
through 149, 151 through 255. The options 1 through 254 are allowed to be configured
using the option number. Options that have option names support are automatically
configured as optionoption-nameoption-value.
DHCP Server Options
Option
Option Number
Option Name
Description / Notes
subnet-mask
1
Subnet Mask
Specifies the client subnet mask (per RFC
950). This is not configurable using the option command. This option is
configured using the network (dhcp) command.
Network <router
IP> <subnet mask>
time-offset
2
Time offset
Specifies the offset of the subnet of the client in
seconds from UTC.
routers
3
Router Option
Specifies an IP addresses of the default router on the
client subnet. Only one router can be specified.
Note: Option 3 is not
supported on non-default VRFs and management VRFs.
Note: Option 3 functions
only when there is no previously configured route on the DHCP
client. If the route received by the DHCP client from the DHCP
server is already configured on the client, the following syslog
message is displayed: DHCP: Failed to configure default gateway.
time-servers
4
Time Server
Specifies a list of Time Servers
available to the client. Time Servers are listed in order of preference.
ien116-name-servers
5
Name Server
Specifies a list of Name Servers
available to the client. Name Servers are listed in order of preference.
domain-name-servers
6
Domain Name Server
Specifies a list of Domain Name System
(RFC 1035) name servers available to the client. Servers are listed in
order of preference.
log-servers
7
Log Server
Specifies a list of UDP log servers
available to the client. Servers are listed in order of preference.
cookie-servers
8
Cookie Server
Specifies the list of RFC 865 cookie servers available to
the client. Servers are listed in order of preference.
lpr-servers
9
LPR Server
Specifies a list of Line Printer Servers
available to the client. Servers are listed in order of preference.
impress-servers
10
Impress Server
Specifies a list of Imagen Impress
Servers available to the client. Servers are listed in order of
preference.
resource-location-servers
11
RLP Server
Specifies a list of Resource Location
Servers available to the client. Servers are listed in order of
preference.
host-name
12
Hostname
Configures the host name that can be
assigned to the DHCP clients.
boot-size
13
Boot size
Specifies the length of the default boot image for the
client in 512-octet blocks.
merit-dump
14
Merit dump
Specifies the path name of the core file of the client
when the client crashes.
domain-name
15
Domain name
Specifies the domain name the client
should use when resolving host names using the Domain Name System.
swap-server
16
Swap Server
Specifies the IP address of the client
Swap Server.
root-path
17
Root Path
Specifies the path name (entered as an
ASCII character string) that contains the client root disk.
extensions-path
18
Extension Path
Specifies a file, retrievable through TFTP, that contains
information that can be interpreted in the same way as the
vendor-extension field within the BOOTP.
ip-forwarding
19
IP forwarding
Specifies if the client should configure its IP layer
for packet forwarding.
non-local-source-routing
20
Non-local source routing
Specifies a flag to enable or disable non-local source
route forwarding in the client.
policy-filterip-addressnetwork
mask
21
Policy Filter
Specifies Policy Filters for non-local
source routing. The filters consist of a list of IP addresses and masks
that specify destination/mask pairs with which to filter incoming source
routes. Any source-routed datagram whose next-hop address does not match
one of the filters should be discarded by the client.
max-dgram-reassembly
22
Maximum datagram reassembly
Specifies the maximum size datagram that the client
can reassemble.
default-ip-ttl
23
Default IP TTL
Specifies the default time-to-live that the client
should use on outgoing datagrams.
path-mtu-aging-timeout
24
Path MTU aging timeout
Specifies the timeout (in seconds) to use when aging
Path MTU values discovered.
path-mtu-plateau-table
25
Path MTU plateau table
Specifies a table of MTU sizes to use when performing
Path MTU Discovery.
interface-mtu
26
Interface MTU
Specifies the MTU to use for the interface.
all-subnets-local
27
All subnets local
Specifies that all connected subnets use the same MTU.
broadcast-address
28
Broadcast Address
Specifies the Broadcast Address in use on
the client subnet.
perform-mask-discovery
29
Perform mask discovery
Specifies a table of MTU sizes to use when performing
Path MTU Discovery.
mask-supplier
30
Mask Supplier
Specifies if the client responds to subnet mask
requests using ICMP.
router-discovery
31
Router Discovery
Specifies if the client should perform Router
Discovery.
router-solicitation-address
32
Router Request
Specifies the address to which the client
should transmit router solicitation requests.
static-routesdestination
ip-addressstatic-route
33
Static Route
Specifies a list of Static Routes that
the client should install in its routing cache. If multiple routes to
the same destination are specified, they are listed in descending order
of priority. The routes consist of a list of IP address pairs. The first
address is the destination address, and the second address is the router
for the destination. Note that the default route (0.0.0.0) is an illegal
destination for a static route.
trailer-encapsulation
34
Trailer encapsulation
Specifies if the client uses trailers when using the
ARP protocol.
arp-cache-timeout
35
ARP cache timeout
Specifies the timeout in seconds for ARP cache
entries.
ieee802-3-encapsulation
36
IEEE 802-3 encapsulation
Specifies if the client should use Ethernet Version 2
(RFC 894) or IEEE 802.
default-tcp-ttl
37
Default TCP TTL
Specifies the default TTL that the client should use
when sending TCP segments.
tcp-keepalive-interval
38
TCP keepalive interval
Specifies the TCP keepalive interval timeout value
used by the client.
tcp-keepalive-garbage
39
TCP keepalive garbage
Specifies a flag to enable or disable TCP keepalive
garbage in the client.
nis-domain
40
NIS Domain
Specifies the NIS domain (entered as an
ASCII character string) for the client.
nis-servers
41
NIS Servers
Specifies a list of IP addresses for NIS
servers available to the client. Servers are listed in order of
preference.
ntp-servers
42
NTP Servers
Specifies a list of IP addresses for NTP
servers available to the client. Servers are listed in order of
preference.
Specifies vendor-specific information.
This allows clients and servers to exchange vendor-specific information.
The vendor is specified in the Vendor Class Identifier option (option
60).
netbios-name-servers
44
NetBIOS Name Srv
Specifies a list of NetBIOS Name Servers
(NBNS) (RFC 1001 and RFC 1002). NBNS servers are listed in order of
preference.
netbios-dd-server
45
NetBIOS Dist Srv
Specifies a list of NetBIOS Datagram
Distribution Servers (NBDD) servers (RFC 1001 and RFC 1002). NBDD
servers are listed in order of preference.
netbios-node-type
46
NetBios Node Type
Specifies the NetBIOS node type option.
netbios-scope
47
NetBIOS Scope
Specifies the NetBIOS over TCP/IP scope
parameter (RFC 1001 and RFC 1002) for the client.
font-servers
48
X Window Font
Specifies a list of IP addresses of X
Window System Font servers available to the client. X Window System Font
servers are listed in order of preference.
x-display-manager
49
X Window Manager
Specifies a list of IP addresses of X
Window System Display Managers available to the client. X Window System
Display Managers are listed in order of preference.
dhcp-requested-address
50
Address Request
Specifies an IP address used in a client
request (DHCPDISCOVER) to allow the client to request a particular IP
address be assigned.
dhcp-lease-time
51
DHCP Lease Time
Specifies the DHCP lease time.
dhcp-option-overload
52
DHCP Option Overload
Indicates the DHCP 'sname' or 'file' fields are overloaded by using them
to carry DHCP options
dhcp-message-type
53
DHCP Message Type
Specifies the type of DHCP message contained in the DHCP packet.
dhcp-server-identifier
54
DHCP Server Identifier
Specifies the IP address of the server.
dhcp-parameter-request-listlist-of-integers
55
DHCP Parameter Request List
Specifies the options to be sent to the client.
dhcp-message
56
DHCP Message
This option is used by a DHCP server to provide an error
message to a DHCP client in a DHCPNAK message in the event of a failure.
dhcp-max-message-size
57
DHCP Maximum Message Size
DHCP maximum message size. Used as default, if not provided by the
client.
dhcp-renewal-time
58
DHCP Renewal Time
Specifies the renewal time in the DHCP client.
dhcp-rebinding-time
59
DHCP Rebinding Time
Specifies the rebinding time in the DHCP client.
vendor-class-identifierstring
60
Vendor Class Identifier
Specifies the Vendor Class Identifier.
This is used in conjunction with option 43 (Vendor Specific
information), allowing clients and servers to exchange vendor-specific
information.
dhcp-client-identifier
61
DHCP Client Identifier
Specifies the DHCP client identifier.
nwip-domain
62
NetWare/IP Domain
Specifies the NetWare/IP Domain Name used
by the NetWare/IP product.
nwip-suboptions
63
NetWare sub-options
Specifies a sequence of suboptions for NetWare/IP clients
(RFC2242).
nisplus-domain
64
NIS-Domain-Name
Specifies the NIS+ domain (entered as an
ASCII character string) for the client.
nisplus-servers
65
NIS-Server-Addr
Specifies a list of IP addresses for NIS+
servers available to the client. Servers are listed in order of
preference.
tftp-server-name
66
TFTP server hostname or IP address
Specifies the address or name of the TFTP
server available to the client.
bootfile-name
67
Boot File name
Specifies a boot image to be used by the
client.
mobile-ip-home-agent
68
Home-Agent-Addrs
Specifies a list of IP addresses for
Mobile IP Home Agents available to the client. Agents are listed in
order of priority.
smtp-server
69
SMTP-Server
Specifies a list of Simple Mail Transport
Protocol (SMTP) Servers available to the client. Servers are listed in
order of priority.
pop-server
70
POP3-Server
Specifies a list of Post Office Protocol
(POP3) Servers available to the client. Servers are listed in order of
priority.
nntp-server
71
NNTP-Server
Specifies a list of Network News Transport Protocol (NNTP)
Servers available to the client. Servers are listed in order of
priority.
www-server
72
WWW-Server
Specifies a list of World Wide Web (WWW)
Servers available to the client. Servers are listed in order of
priority.
finger-server
73
Finger-Server
Specifies a list of Finger Servers available to the client.
Servers are listed in order of preference.
irc-server
74
IRC-Server
Specifies a list of Internet Relay Chat
(IRC) Servers available to the client. Servers are listed in order of
priority.
streettalk-serverip-address
75
StreetTalk-Server
Specifies a list of StreetTalk Servers
available to the client. Servers are listed in order of priority.
streettalk-directory-assistance-serverip-address
76
STDA-Server
Specifies a list of StreetTalk Directory
Assistance (STDA)Servers available to the client. Servers are listed in
order of priority.
user-class
77
User Class
Specifies identifying information to the DHCP
client.
slp-directory-agent
78
SLP Directory Agent
Specifies the IP addresses of SLP Directory Agents,
and flags to set the use of these addresses.
slp-service-scope
79
SLP Service Scope
Specifies a list of service scopes for SLP, and
whether the use of this list is mandatory.
nds-servers
85
NDS Servers
Specifies the IP addresses for Novell
Directory Services (NDS) servers available to the client. Servers are
listed in order of priority.
nds-tree-namestring
86
NDS Tree Name
Specifies the name of the Novell
Directory Services (NDS) Tree to which the client will connect.
nds-context
87
NDS Context
Specifies the name of the initial Netware Directory
Service for an NDS client.
bcms-controller-names
88
BCMCS Domain List
Specifies a list of Broadcast and Multicast Service (BCMCS)
Controller domain names.
bcms-controller-address
89
BCMCS IPv4 addr
Specifies a list of IP addresses for Broadcast and
Multicast Service (BCMCS) controllers. Controllers are listed in order
of preference56.
client-last-transaction-time
91
Client last transaction time
Specifies the last client transaction time in units.
associated-ip
92
Associated IP
Specifies that all IP addresses associated with a
given DHCP client are listed.
pxe-system-type
93
PXE System Type
A list of one or more 16-bit integers that allows a client to specify
its pre-boot architecture type(s).
pxe-interface-id
94
Client NDI
Specifies the Network Interface
Identifier (NDI) for the client.
option 95
95
LDAP
This option is supported if the option
value type is IP, ASCII, or HEX
pxe-client-id
97
PXE client ID
Allows a client to specify its PXE client identity.
uap-servers
98
User-Auth
Specifies a list of URLs, each pointing to a user
authentication service that is capable of processing authentication
requests encapsulated in the User Authentication Protocol (UAP).
If a URL does not
contain a port component, the normal default port is assumed (port
80 for http and port 443 for https).
If a URL does not
include a path component, the path /uap is assumed.
option 100
100
Pcode
Specifies the TZ-POSIX string used to
provide timezone details.
option 101
101
Tcode
Specifies the TZ-Database string used to
provide timezone details.
option value
102 - 111
Removed/Unassigned
These options are supported if the value
type is defined as IP, ASCII, or HEX
netinfo-server-addressip-address
112
Netinfo Address
This option is supported if the option
value type is IP, ASCII, or HEX
netinfo-server-tagstring
113
Netinfo Tag
This option is supported if the option
value type is IP, ASCII, or HEX
default-url
114
URL
This option is supported if the option
value type is IP, ASCII, or HEX
subnet-selection
118
Subnet Selection
Specifies the client preferred subnet for address
assignment.
domain-search
119
Domain Search
Specifies a Domain Names search list used by the
client to locate not-fully-qualified domain names.
vivsostring
125
V-I VendorSpeciInfo
Specifies Vendor-Identified vendor specific information.
Only the string value is accepted.
option value
126 - 127
Removed/Unassigned
These options are supported if the option
value type is IP, ASCII, or HEX
option value
128 - 135
PXE-VendorSpecific
These options are supported if the option
value type is IP, ASCII, or HEX
option value
137
V4_LOST
Specifies the fully qualified domain name
(FQDN) to be used by the client to locate a Location-to-Service
Translation (LoST) server.
option value
141
SIP UA Domains
Specifies a list of domain names to
search for Session Initiation Protocol (SIP) User Agent Configuration.
option value
142
IPv4-ANDSF
Specifies the IP addresses for Access
Network Discover and Selection Function (ANDSF) Servers available to the
client. The servers are listed in order of priority.
option value
146
RDNSS Selection
This option is supported if the option
value type is IP, ASCII, or HEX
option value
147 - 148
Unassigned
These options are supported if the option value type is IP,
ASCII, or HEX
tftp-server-address
150
TFTP Server Addr
Specifies the address of the TFTP Server available to the
client.
option value
156
dhcp-state
This option is supported if the option
value type is IP, ASCII, or HEX
option value
160
Captive-Portal
This option is supported if the option
value type is IP, ASCII, or HEX
option value
161 - 174
Unassigned
These options are supported if the option
value type is IP, ASCII, or HEX
option value
175
Etherboot
This option is supported if the option
value type is IP, ASCII, or HEX
option value
176
IP Tele-VoiceSrvr
Configures the IP telephone voice
parameters for Avaya IP phones running as DHCP clients.
option value
177
PktCable-CableHome
This option is supported if the option
value type is IP, ASCII, or HEX
option value
178 - 206
Unassigned
These options are supported if the option value type is IP,
ASCII, or HEX
option value
209
Config File
Specifies the configuration file to be
used in a PXELINUX environment.
option value
210
Path Prefix
Specifies a path prefix for the configuration file used in
a PXELINUX environment.
option value
213
V4_ACCESS_DOMAIN
Specifies the access network domain name
available to the client for the purposes of discovering a Local
Information Server (LIS).
option value
214 - 218
Unassigned
These options are supported if the option
value type is IP, ASCII, or HEX
option value
221
VSS
This option is supported if the option
value type is IP, ASCII, or HEX
option value
222 - 223
Unassigned
These options are supported if the option
value type is IP, ASCII, or HEX
option value
224 - 241
Reserved
These options are supported if the option
value type is IP, ASCII, or HEX
option value
242
IP Tele-DataSrvr
Configures the IP telephone data
parameters for Avaya IP phones running as DHCP clients.
option value
243 - 251
Reserved
These options are supported if the option
value type is P, ASCII, or HEX
option value
252
WPAD
Configures the Proxy-Auto Config (PAC)
file location string for the Web Proxy Auto-Discovery (WPAD) supported
DHCP clients.
option value
253 - 254
Reserved
These options are supported if the option
value type is IP, ASCII, or HEX
A DHCP server assigns and manages IPv4 addresses from multiple address pools, using
dynamic address allocation. The DHCP server also contains the relay agent to forward
DHCP broadcast messages to network segments that do not support these types of messages.
The list of supported DHCP options is extensive. However, the number of options that
can be passed to the client is limited by the size of the ACK packet. It is recommended
that you configure essential options only for the specific DHCP server address pool.
The following options (if configured) are prioritized, with additional options added
as needed:
3 - Router Option
6 - Domain Name Server
12 - Hostname
15 - Domain name
66 - TFTP server hostname or IP address
67 - Boot file name
60 - Vendor-Specific Information
DHCP options are not validated by the DHCP server. You must ensure the values are
configured correctly.
Upgrade Considerations
In FastIron 08.0.61 or earlier
releases, it was possible to configure a subset of these DHCP options using specific
commands. For example, dhcp-default-router allows configuration of the DHCP default router
(which is now also configurable using DHCP option 3). When upgrading to FastIron
08.0.70 or later releases, any configured DHCP options are retained. However,
the
configuration is stored and shown in the new options format. The following table
shows the options available in earlier releases and a mapping between the current
option format and the corresponding commands available in earlier releases.
Option Command Mappings between Current Formats and Previous
Releases
Option Number and Name
Command in Release 08.0.70 and Later
Command in Release 08.0.61 and Earlier
1 - Subnet Mask
networkrouter-IPsubnet mask
Note that
this essential option is configured using the network command. It is not configurable using
the option command.
networkrouter-IPsubnet mask
3 - Router Option
option 3
iprouter -IP
dhcp-default-router router
-IP
6 - Domain Name Server
option 6
ip server-IP-address
dns-server server-IP-address
12 - Hostname
option 12
ascii hostname
host-namehostname
15 - Domain name
option 15
asciidomain-name
domain-nameascii-string-domain-name
47 - NetBIOS over TCP/IP Name Server
option 47
ipServer-IP
netbios-name-server Server-IP
49 - X Window System Display Manager
option 49
ipXWindow-manager-IP
xwindow-managerXWindow-manager-IP
66 - TFTP server hostname
option 66
asciiTFTP-server-hostname
tftp-serverTFTP-server-hostname
67 - Bootfile name
option 67
ascii
bootfile-name
bootfilebootfile-name
150 - TFTP server IP address
option
150 ipTFTP-server-IP
tftp-serverTFTP-server-IP
176 - ip-telephony voice server
option
176 mcipadd mcport,…
ip-telephony voice mcipadd mcport,…
242 - ip-telephony data server
option 242
mcipadd mcport,…
ip-telephony data mcipadd mcport,…
252 - Proxy-Auto Config (PAC)
option
252 asciiURL-to-config-file
wpad
URL-to-config-file
60 - Vendor-Specific Information
option 60
asciiVCI
vendor-classascii-string-VCI
Note that the existing commands are still supported. However, it is recommended that
you configure these using the option command where appropriate. The configuration
is stored and shown in the options format, irrespective of whether the option is configured
using the option command or the commands available in previous releases.
When upgrading from any previous version to FastIron 09.0.00, the
deploy and ip dhcp-server relay-agent-echo
enable commands are not available and will not be seen in the running
configuration after upgrade.
Follow the below process for the ISC options:
If the option is of type ASCII string, convert the option value to ASCII string
and change the option type to "ascii".
If the option is of type Hex string, convert
the option value to HEX string and change the option type to "hex".
If the option is of type integer, convert the option value as ASCII to integer,
if it is a valid integer value, and save the configuration as "option
<option-num> integer <option-value>", or convert the option value as hex
to integer, if it is a valid integer value, and save the config as "option
<option-num> integer <option-value>", or ignore the option value if it is
of type IP address.
If the option is of type bool in 9000,
convert the option value from ascii to integer; if it is a valid integer value
and greater than zero, save the bool as true; if it is zero, save the bool as
false. Alternatively, convert the option value from hex to integer; if it is
valid integer value and greater than zero, save the bool as true; if it is zero,
then save the bool as false. Another alternative is to ignore the option value
if it is of type IP address.
If the option is of type IP address, check
that the option supports the list of IPs or single IPs. If the list of IPs are
supported, no change is required. If single IP is supported, save the first IP
address and remove the other IP addresses. If the option is slp-service-scope,
configure the bool flag as true always and save the option value as ASCII
string. If the option is slp-directory-agent, configure the bool flag as true
always, and save the IP addresses configured.
For the policy-filter(21) options, delete the option type IP. If there are three
IP addresses, remove the last IP address. In FastIron 09.0.00, option 21 accepts
destination IP and subnet mask as a pair. This means that option 21 configured
in previous releases are not applied when upgrading to FI 09.0.00.
For the static-route(33) option, delete the option type IP from the command. If
there are three IP addresses, remove the last IP address.