DHCP Client and Server
Document revision: | 2.8 (December 12, 2007, 11:43 GMT) |
Applies to: | V3.0 |
General Information
Summary
The DHCP (Dynamic Host Configuration Protocol) is needed for easy distribution of IP addresses in a network. The MikroTik RouterOS implementation includes both server and client parts and is compliant with RFC2131.
General usage of DHCP:
- IP assignment in LAN, cable-modem, and wireless systems
- Obtaining IP settings on cable-modem systems
IP addresses can be bound to MAC addresses using static lease feature.
DHCP server can be used with MikroTik RouterOS HotSpot feature to authenticate and account DHCP clients. See the HotSpot Manual for more information.
Quick Setup Guide
This example will show you how to setup DHCP-Server and DHCP-Client on MikroTik RouterOS.
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Setup of a DHCP Server:
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Create an IP address pool
/ip pool add name=dhcp-pool ranges=172.16.0.10-172.16.0.20
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Add a DHCP network which will concern to the network 172.16.0.0/12 and will distribute a gateway with IP address 172.16.0.1 to DHCP clients:
/ip dhcp-server network add address=172.16.0.0/12 gateway=172.16.0.1
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Finally, add a DHCP server:
/ip dhcp-server add interface=wlan1 address-pool=dhcp-pool
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Setup of a DHCP Client (which will get a lease from the DHCP server, configured above).
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Add the DHCP client:
/ip dhcp-client add interface=wlan1 use-peer-dns=yes \ add-default-route=yes disabled=no
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Check whether you have obtained a lease:
[admin@Server] ip dhcp-client> print detail Flags: X - disabled, I - invalid 0 interface=wlan1 add-default-route=yes use-peer-dns=yes status=bound address=172.16.0.20/12 gateway=172.16.0.1 dhcp-server=192.168.0.1 primary-dns=159.148.147.194 expires-after=2d23:58:52 [admin@Server] ip dhcp-client>
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Specifications
Packages required: dhcpLicense required: Level1
Submenu level: /ip dhcp-client, /ip dhcp-server, /ip dhcp-relay
Standards and Technologies: DHCP
Description
The DHCP protocol gives and allocates IP addresses to IP clients. DHCP is insecure by design and should only be used in trusted networks. DHCP server always listens on UDP 67 port, DHCP client - on UDP 68 port. The initial negotiation involves communication between broadcast addresses (on some phases sender will use source address of 0.0.0.0 and/or destination address of 255.255.255.255). You should be aware of this when building firewall.
Additional Resources
DHCP Client Setup
Submenu level: /ip dhcp-clientDescription
The MikroTik RouterOS DHCP client may be enabled on any Ethernet-like interface. There can only be one active DHCP client per interface. The client will accept an address, netmask, default gateway, two DNS server addresses and two NTP server addresses. All other information is ignored. The received IP address with the respective netmask will be added to the corresponding interface. The default gateway will be added to the routing table as a dynamic entry. Should the DHCP client be disabled or not renew an address, the dynamic default route will be removed. If there is already a default route installed prior the DHCP client obtains one, the route obtained by the DHCP client will be shown as invalid.
Property Description
add-default-route (yes | no; default: yes) - whether to add the default route to the gateway specified by the DHCP serveraddress (read-only: IP address/netmask) - IP address and netmask, which is assigned to DHCP Client from the Serverclient-id (text) - corresponds to the settings suggested by the network administrator or ISP. Commonly it is set to the client's MAC address, but it may as well be any text string dhcp-server (read-only: IP address) - IP address of the DHCP serverexpires-after (read-only: time) - time, when the lease expires (specified by the DHCP server)gateway (read-only: IP address) - IP address of the gateway which is assigned by DHCP serverhost-name (text) - the host name of the client as sent to a DHCP serverinterface (name) - any Ethernet-like interface (this includes wireless and EoIP tunnels) on which the client searches for a DHCP serverprimary-dns (read-only: IP address) - IP address of the primary DNS server, assigned by the DHCP serverprimary-ntp (read-only: IP address) - IP address of the primary NTP server, assigned by the DHCP serversecondary-dns (read-only: IP address) - IP address of the secondary DNS server, assigned by the DHCP serversecondary-ntp (read-only: IP address) - IP address of the secondary NTP server, assigned by the DHCP serverstatus (read-only: bound | error | rebinding... | renewing... | requesting... | searching... | stopped) - shows the status of DHCP slientuse-peer-dns (yes | no; default: yes) - whether to accept the DNS settings advertized by DHCP server (they will override the settings put in the /ip dns submenu)use-peer-ntp (yes | no; default: yes) - whether to accept the NTP settings advertized by DHCP server (they will override the settings put in the /system ntp client submenu)Command Description
release - release current binding and restart DHCP clientrenew - renew current leases. If the renew operation was not successful, client tries to reinitialize lease (i.e. it starts lease request procedure (rebind) as if it had not received an IP address yet)Notes
If host-name property is not specified, client's system identity will be sent in the respective field of DHCP request.
If client-id property is not specified, client's MAC address will be sent in the respective field of DHCP request.
If use-peer-dns property is enabled, the DHCP client will unconditionally rewrite the settings in /ip dns submenu. In case two or more DNS servers were received, first two of them are set as primary and secondary servers respectively. In case one DNS server was received, it is put as primary server, and the secondary server is left intact.
Example
To add a DHCP client on ether1 interface:
/ip dhcp-client add interface=ether1 disabled=no [admin@MikroTik] ip dhcp-client> print detail Flags: X - disabled, I - invalid 0 interface=ether1 add-default-route=yes use-peer-dns=yes use-peer-ntp=yes status=bound address=192.168.0.65/24 gateway=192.168.0.1 dhcp-server=192.168.0.1 primary-dns=192.168.0.1 primary-ntp=192.168.0.1 expires-after=9m44s [admin@MikroTik] ip dhcp-client>
DHCP Server Setup
Submenu level: /ip dhcp-serverDescription
The router supports an individual server for each Ethernet-like interface. The MikroTik RouterOS DHCP server supports the basic functions of giving each requesting client an IP address/netmask lease, default gateway, domain name, DNS-server(s) and WINS-server(s) (for Windows clients) information (set up in the DHCP networks submenu)
In order DHCP server to work, you must set up also IP pools (do not include the DHCP server's own IP address into the pool range) and DHCP networks.
It is also possible to hand out leases for DHCP clients using the RADIUS server, here are listed the parameters for used in RADIUS server.
Access-Request:
- NAS-Identifier - router identity
- NAS-IP-Address - IP address of the router itself
- NAS-Port - unique session ID
- NAS-Port-Type - Ethernet
- Calling-Station-Id - client identifier (active-client-id)
- Framed-IP-Address - IP address of the client (active-address)
- Called-Station-Id - name of DHCP server
- User-Name - MAC address of the client (active-mac-address)
- Password - ""
Access-Accept:
- Framed-IP-Address - IP address that will be assigned to client
- Framed-Pool - ip pool from which to assign ip address to client
- Rate-Limit - Datarate limitation for DHCP clients. Format is: rx-rate[/tx-rate] [rx-burst-rate[/tx-burst-rate] [rx-burst-threshold[/tx-burst-threshold] [rx-burst-time[/tx-burst-time][priority] [rx-rate-min[/tx-rate-min]]]]. All rates should be numbers with optional 'k' (1,000s) or 'M' (1,000,000s). If tx-rate is not specified, rx-rate is as tx-rate too. Same goes for tx-burst-rate and tx-burst-threshold and tx-burst-time. If both rx-burst-threshold and tx-burst-threshold are not specified (but burst-rate is specified), rx-rate and tx-rate are used as burst thresholds. If both rx-burst-time and tx-burst-time are not specified, 1s is used as default. Priority takes values 1..8, where 1 implies the highest priority, but 8 - the lowest. If rx-rate-min and tx-rate-min are not specified rx-rate and tx-rate values are used. The rx-rate-min and tx-rate-min values can not exceed rx-rate and tx-rate values.
- Ascend-Data-Rate - tx/rx data rate limitation if multiple attributes are provided, first limits tx data rate, second - rx data rate. If used together with Ascend-Xmit-Rate, specifies rx rate. 0 if unlimited
- Ascend-Xmit-Rate - tx data rate limitation. It may be used to specify tx limit only instead of sending two sequental Ascend-Data-Rate attributes (in that case Ascend-Data-Rate will specify the receive rate). 0 if unlimited
- Session-Timeout - max lease time (lease-time)
Property Description
add-arp (yes | no; default: no) - whether to add dynamic ARP entry:after-2sec-delay - to clients request for an address, dhcp server will wait 2 seconds and if there is another request from the client after this period of time, then dhcp server will offer the address to the client or will send DHCPNAK, if the requested address is not available from this server
no - dhcp server ignores clients requests for addresses that are not available from this server
yes - to clients request for an address that is not available from this server, dhcp server will send negative acknowledgment (DHCPNAK)
static - offer only static leases to BOOTP clients
dynamic - offer static and dynamic leases for BOOTP clients
255.255.255.255 - the DHCP server should be used for any incomming request from a DHCP relay except for those, which are processed by another DHCP server that exists in the /ip dhcp-server submenu
Notes
Client will only receive a DHCP lease in case it is directly reachable by its MAC address through that interface (some wireless bridges may change client's MAC address).
If authoritative property is set to yes, the DHCP server is sending rejects for the leases it cannot bind or renew. It also may (although not always) help to prevent the network users to run their own DHCP servers illicitly, disturbing the proper way the network should be functioning.
If relay property of a DHCP server is not set to 0.0.0.0 the DHCP server will not respond to the direct requests from clients.
Example
To add a DHCP server to interface ether1, lending IP addresses from dhcp-clients IP pool for 2 hours:
/ip dhcp-server add name=dhcp-office disabled=no address-pool=dhcp-clients \ interface=ether1 lease-time=2h [admin@MikroTik] ip dhcp-server> print Flags: X - disabled, I - invalid # NAME INTERFACE RELAY ADDRESS-POOL LEASE-TIME ADD-ARP 0 dhcp-office ether1 dhcp-clients 02:00:00 [admin@MikroTik] ip dhcp-server>
Store Leases on Disk
Submenu level: /ip dhcp-server configDescription
Leases are always stored on disk on graceful shutdown and reboot. If they would be saved on disk on every lease change, a lot of disk writes would happen. There are no problems if it happens on a hard drive, but is very bad for Compact Flash (especially, if lease times are very short). To minimize writes on disk, all changes are saved on disk every store-leases-disk seconds. If this time will be very short (immediately), then no changes will be lost even in case of hard reboots and power losts. But, on CF there may be too many writes in case of short lease times (as in case of hotspot). If this time will be very long (never), then there will be no writes on disk, but information about active leases may be lost in case of power loss. In these cases dhcp server may give out the same ip address to another client, if first one will not respond to ping requests.
Property Description
store-leases-disk (time-interval | immediately | never; default: 5min) - how frequently lease changes should be stored on diskDHCP Networks
Submenu level: /ip dhcp-server networkProperty Description
address (IP address/netmask) - the network DHCP server(s) will lend addresses fromboot-file-name (text) - Boot file namedhcp-option (text) - add additional DHCP options from /ip dhcp-server option list. You cannot redefine parameters which are already defined in this submenu:Router (code 3) - gateway
Domain-Server (code 6) - dns-server
Domain-Name (code 15) - domain
NTP-Servers (code 42) - ntp-server
NETBIOS-Name-Server (code 44) - wins-server
Notes
The address field uses netmask to specify the range of addresses the given entry is valid for. The actual netmask clients will be using is specified in netmask property.
DHCP Server Leases
Submenu level: /ip dhcp-server leaseDescription
DHCP server lease submenu is used to monitor and manage server's leases. The issued leases are showed here as dynamic entries. You can also add static leases to issue a particular client (identified by MAC address) the desired IP address.
Generally, the DHCP lease it allocated as follows:
- an unused lease is in waiting state
- if a client asks for an IP address, the server chooses one
- if the client will receive statically assigned address, the lease becomes offered, and then bound with the respective lease time
- if the client will receive a dynamic address (taken from an IP address pool), the router sends a ping packet and waits for answer for 0.5 seconds. During this time, the lease is marked testing
- in case, the address does not respond, the lease becomes offered, and then bound with the respective lease time
- in other case, the lease becomes busy for the lease time (there is a command to retest all busy addresses), and the client's request remains unanswered (the client will try again shortly)
A client may free the leased address. The dynamic lease is removed, and the allocated address is returned to the address pool. But the static lease becomes busy until the client will reacquire the address.
Note that the IP addresses assigned statically are not probed.
Property Description
active-address (read-only: IP address) - actual IP address for this leaseactive-client-id (read-only: text) - actual client-id of the clientactive-mac-address (read-only: MAC address) - actual MAC address of the clientactive-server (read-only: list) - actual dhcp server, which serves this clientaddress (IP address) - specify ip address (or ip pool) for static leasetesting - testing whether this address is used or not (only for dynamic leases) by pinging it with timeout of 0.5s
authorizing - waiting for response from radius server
busy - this address is assigned statically to a client or already exists in the network, so it can not be leased
offered - server has offered this lease to a client, but did not receive confirmation from the client
bound - server has received client's confirmation that it accepts offered address, it is using it now and will free the address not later, than the lease time will be over
Command Description
check-status - check status of a given busy dynamic lease, and free it in case of no responsemake-static - convert a dynamic lease to a static oneNotes
If rate-limit is specified, a simple queue is added with corresponding parameters when lease enters bound state. Arp entry is added right after adding of queue is done (only if add-arp is enabled for dhcp server). To be sure, that client cannot use his ip address without getting dhcp lease and thus avoiding rate-limit, reply-only mode must be used on that ethernet interface.
Even though client address may be changed (with adding a new item) in lease print list, it will not change for the client. It is true for any changes in the DHCP server configuration because of the nature of the DHCP protocol. Client tries to renew assigned IP address only when half a lease time is past (it tries to renew several times). Only when full lease time is past and IP address was not renewed, new lease is asked (rebind operation).
the deault mac-address value will never work! You should specify a correct MAC address there.
Example
To assign 10.5.2.100 static IP address for the existing DHCP client (shown in the lease table as item #0):
[admin@MikroTik] ip dhcp-server lease> print Flags: X - disabled, R - radius, D - dynamic, B - blocked # ADDRESS MAC-ADDRESS HOST-NAME SERVER RATE-LIMIT STATUS 0 D 10.5.2.90 00:04:EA:C6:0E:40 switch bound 1 D 10.5.2.91 00:04:EA:99:63:C0 switch bound [admin@MikroTik] ip dhcp-server lease> add copy-from=0 address=10.5.2.100 [admin@MikroTik] ip dhcp-server lease> print Flags: X - disabled, R - radius, D - dynamic, B - blocked # ADDRESS MAC-ADDRESS HOST-NAME SERVER RATE-LIMIT STATUS 0 D 10.5.2.91 00:04:EA:99:63:C0 switch bound 1 10.5.2.100 00:04:EA:C6:0E:40 switch bound [admin@MikroTik] ip dhcp-server lease>
DHCP Alert
Submenu level: /ip dhcp-server alertDescription
To find any rogue DHCP servers as soon as they appear in your network, DHCP Alert tool can be used. It will monitor ethernet for all DHCP replies and check, whether this reply comes from a valid DHCP server. If reply from unknown DHCP server is detected, alert gets triggered:
[admin@MikroTik] ip dhcp-server alert>/log print 00:34:23 dhcp,critical,error,warning,info,debug dhcp alert on Public: discovered unknown dhcp server, mac 00:02:29:60:36:E7, ip 10.5.8.236 [admin@MikroTik] ip dhcp-server alert>
When the system alerts about a rogue DHCP server, it can execute a custom script.
As DHCP replies can be unicast, rogue dhcp detector may not receive any offer to other dhcp clients at all. To deal with this, rogue dhcp detector acts as a dhcp client as well - it sends out dhcp discover requests once a minute
Property Description
alert-timeout (none/time; default: none) - time, after which alert will be forgotten. If after that time the same server will be detected, new alert will be generatedNotes
All alerts on an interface can be cleared at any time using command: /ip dhcp-server alert reset-alert <interface>
Note, that e-mail can be sent, using /system logging action add target=email
DHCP Option
Submenu level: /ip dhcp-server optionDescription
With help of DHCP Option list, it is possible to define additional custom options for DHCP Server to advertise.
Property Description
code (integer: 1..254) - dhcp option code. All codes are available at http://www.iana.org/assignments/bootp-dhcp-parametersname (name) - descriptive name of the optionvalue (text) - parameter's value in form of a string. If the string begins with "0x", it is assumed as a hexadecimal valueNotes
The defined options you can use in /ip dhcp-server network submenu
According to the DHCP protocol, a parameter is returned to the DHCP client only if it requests this parameter, specifying the respective code in DHCP request Parameter-List (code 55) attribute. If the code is not included in Parameter-List attribute, DHCP server will not send it to the DHCP client.
Example
This example shows how to set DHCP server to reply on DHCP client's Hostname request (code 12) with value Host-A.
Add an option named Option-Hostname with code 12 (Hostname) and value Host-A:
[admin@MikroTik] ip dhcp-server option> add name=Hostname code=12 \ value="Host-A" [admin@MikroTik] ip dhcp-server option> print # NAME CODE VALUE 0 Option-Hostname 12 Host-A [admin@MikroTik] ip dhcp-server option>
Use this option in DHCP server network list:
[admin@MikroTik] ip dhcp-server network> add address=10.1.0.0/24 \ \... gateway=10.1.0.1 dhcp-option=Option-Hostname dns-server=159.148.60.20 [admin@MikroTik] ip dhcp-server network> print detail 0 address=10.1.0.0/24 gateway=10.1.0.1 dns-server=159.148.60.20 dhcp-option=Option-Hostname [admin@MikroTik] ip dhcp-server network>
Now the DHCP server will reply with its Hostname Host-A to DHCP client (if requested)
DHCP Relay
Submenu level: /ip dhcp-relayDescription
DHCP Relay is just a proxy that is able to receive a DHCP request and resend it to the real DHCP server
Property Description
delay-threshold (time; default: none) - if secs field in DHCP packet is smaller than delay-threshold, then this packet is ignoreddhcp-server (text) - list of DHCP servers' IP addresses which should the DHCP requests be forwarded tointerface (name) - interface name the DHCP relay will be working onlocal-address (IP address; default: 0.0.0.0) - the unique IP address of this DHCP relay needed for DHCP server to distinguish relays:Notes
DHCP relay does not choose the particular DHCP server in the dhcp-server list, it just send the incoming request to all the listed servers.
Example
To add a DHCP relay named relay on ether1 interface resending all received requests to the 10.0.0.1 DHCP server:
[admin@MikroTik] ip dhcp-relay> add name=relay interface=ether1 \ \... dhcp-server=10.0.0.1 disabled=no [admin@MikroTik] ip dhcp-relay> print Flags: X - disabled, I - invalid # NAME INTERFACE DHCP-SERVER LOCAL-ADDRESS 0 relay ether1 10.0.0.1 0.0.0.0 [admin@MikroTik] ip dhcp-relay>
Question&Answer-Based Setup
Command name: /ip dhcp-server setupQuestions
addresses to give out (text) - the pool of IP addresses DHCP server should lease to the clientsdhcp address space (IP address/netmask; default: 192.168.0.0/24) - network the DHCP server will lease to the clientsdhcp relay (IP address; default: 0.0.0.0) - the IP address of the DHCP relay between the DHCP server and the DHCP clientsdhcp server interface (name) - interface to run DHCP server ondns servers (IP address) - IP address of the appropriate DNS server to be propagated to the DHCP clientsgateway (IP address; default: 0.0.0.0) - the default gateway of the leased networklease time (time; default: 3d) - the time the lease will be validNotes
Depending on current settings and answers to the previous questions, default values of following questions may be different. Some questions may disappear if they become redundant (for example, there is no use of asking for 'relay' when the server will lend the directly connected network)
Example
To configure DHCP server on ether1 interface to lend addresses from 10.0.0.2 to 10.0.0.254 which belong to the 10.0.0.0/24 network with 10.0.0.1 gateway and 159.148.60.2 DNS server for the time of 3 days:
[admin@MikroTik] ip dhcp-server> setup Select interface to run DHCP server on dhcp server interface: ether1 Select network for DHCP addresses dhcp address space: 10.0.0.0/24 Select gateway for given network gateway for dhcp network: 10.0.0.1 Select pool of ip addresses given out by DHCP server addresses to give out: 10.0.0.2-10.0.0.254 Select DNS servers dns servers: 159.148.60.20 Select lease time lease time: 3d [admin@MikroTik] ip dhcp-server>
The wizard has made the following configuration based on the answers above:
[admin@MikroTik] ip dhcp-server> print Flags: X - disabled, I - invalid # NAME INTERFACE RELAY ADDRESS-POOL LEASE-TIME ADD-ARP 0 dhcp1 ether1 0.0.0.0 dhcp_pool1 3d no [admin@MikroTik] ip dhcp-server> network print # ADDRESS GATEWAY DNS-SERVER WINS-SERVER DOMAIN 0 10.0.0.0/24 10.0.0.1 159.148.60.20 [admin@MikroTik] ip dhcp-server> /ip pool print # NAME RANGES 0 dhcp_pool1 10.0.0.2-10.0.0.254 [admin@MikroTik] ip dhcp-server>
Application Examples
Dynamic Addressing, using DHCP-Relay
Let us consider that you have several IP networks 'behind' other routers, but you want to keep all DHCP servers on a single router. To do this, you need a DHCP relay on your network which relies DHCP requests from clients to DHCP server.
This example will show you how to configure a DHCP server and a DHCP relay which serve 2 IP networks - 192.168.1.0/24 and 192.168.2.0/24 that are behind a router DHCP-Relay.
IP addresses of DHCP-Server:
[admin@DHCP-Server] ip address> print Flags: X - disabled, I - invalid, D - dynamic # ADDRESS NETWORK BROADCAST INTERFACE 0 192.168.0.1/24 192.168.0.0 192.168.0.255 To-DHCP-Relay 1 10.1.0.2/24 10.1.0.0 10.1.0.255 Public [admin@DHCP-Server] ip address>
IP addresses of DHCP-Relay:
[admin@DHCP-Relay] ip address> print Flags: X - disabled, I - invalid, D - dynamic # ADDRESS NETWORK BROADCAST INTERFACE 0 192.168.0.1/24 192.168.0.0 192.168.0.255 To-DHCP-Server 1 192.168.1.1/24 192.168.1.0 192.168.1.255 Local1 2 192.168.2.1/24 192.168.2.0 192.168.2.255 Local2 [admin@DHCP-Relay] ip address>
To setup 2 DHCP Servers on DHCP-Server router add 2 pools. For networks 192.168.1.0/24 and 192.168.2.0:
/ip pool add name=Local1-Pool ranges=192.168.1.11-192.168.1.100 /ip pool add name=Local1-Pool ranges=192.168.2.11-192.168.2.100
[admin@DHCP-Server] ip pool> print # NAME RANGES 0 Local1-Pool 192.168.1.11-192.168.1.100 1 Local2-Pool 192.168.2.11-192.168.2.100 [admin@DHCP-Server] ip pool>
Create DHCP Servers:
/ip dhcp-server add interface=To-DHCP-Relay relay=192.168.1.1 \ address-pool=Local1-Pool name=DHCP-1 disabled=no /ip dhcp-server add interface=To-DHCP-Relay relay=192.168.2.1 \ address-pool=Local2-Pool name=DHCP-2 disabled=no
[admin@DHCP-Server] ip dhcp-server> print Flags: X - disabled, I - invalid # NAME INTERFACE RELAY ADDRESS-POOL LEASE-TIME ADD-ARP 0 DHCP-1 To-DHCP-Relay 192.168.1.1 Local1-Pool 3d00:00:00 1 DHCP-2 To-DHCP-Relay 192.168.2.1 Local2-Pool 3d00:00:00 [admin@DHCP-Server] ip dhcp-server>
Configure respective networks:
/ip dhcp-server network add address=192.168.1.0/24 gateway=192.168.1.1 \ dns-server=159.148.60.20 /ip dhcp-server network add address=192.168.2.0/24 gateway=192.168.2.1 \ dns-server 159.148.60.20
[admin@DHCP-Server] ip dhcp-server network> print # ADDRESS GATEWAY DNS-SERVER WINS-SERVER DOMAIN 0 192.168.1.0/24 192.168.1.1 159.148.60.20 1 192.168.2.0/24 192.168.2.1 159.148.60.20 [admin@DHCP-Server] ip dhcp-server network>
Configuration of DHCP-Server is done. Now let's configure DHCP-Relay:
/ip dhcp-relay add name=Local1-Relay interface=Local1 \ dhcp-server=192.168.0.1 local-address=192.168.1.1 disabled=no /ip dhcp-relay add name=Local2-Relay interface=Local2 \ dhcp-server=192.168.0.1 local-address=192.168.2.1 disabled=no
[admin@DHCP-Relay] ip dhcp-relay> print Flags: X - disabled, I - invalid # NAME INTERFACE DHCP-SERVER LOCAL-ADDRESS 0 Local1-Relay Local1 192.168.0.1 192.168.1.1 1 Local2-Relay Local2 192.168.0.1 192.168.2.1 [admin@DHCP-Relay] ip dhcp-relay>
IP Address assignment, using FreeRADIUS Server
Let us consider that we want to assign IP addresses for clients, using the RADIUS server.
We assume that you already have installed FreeRADIUS. Just add these lines to specified files:
users file:
00:0B:6B:31:02:4B Auth-Type := Local, Password == "" Framed-IP-Address = 192.168.0.55
clients.conf file
client 172.16.0.1 { secret = MySecret shortname = Server }
Configure Radius Client on RouterOS:
/radius add service=dhcp address=172.16.0.2 secret=MySecret
[admin@DHCP-Server] radius> print detail Flags: X - disabled 0 service=dhcp called-id="" domain="" address=172.16.0.2 secret="MySecret" authentication-port=1812 accounting-port=1813 timeout=00:00:00.300 accounting-backup=no realm="" [admin@DHCP-Server] radius>
Setup DHCP Server:
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Create an address pool:
/ip pool add name=Radius-Clients ranges=192.168.0.11-192.168.0.100
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Add a DHCP server:
/ip dhcp-server add address-pool=Radius-Clients use-radius=yes interface=Local \ disabled=no
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Configure DHCP networks:
/ip dhcp-server network add address=192.168.0.0/24 gateway=192.168.0.1 \ dns-server=159.148.147.194,159.148.60.20
Now the client with MAC address 00:0B:6B:31:02:4B will always receive IP address 192.168.0.55.