Manual:IPv6/DHCP Server
Applies to RouterOS: v5.9+
Summary
Standards: RFC 3315, RFC 3633
Package: dhcp,ipv6
Starting from v5.9 DHCP-PD server is moved to /ipv6 sub menu
Single DUID is used for client and server identification, only IAID will vary between cients corresponding to their assigned interface.
Client binding creates dynamic pool with timeout set to binding's expiration time (note that now dynamic pools can have a timeout), which will be updated every time binding gets renewed.
When client is bound to prefix, DHCP server adds routing information to know how to reach assigned prefix.
Client bindings in server does not show MAC address anymore (as it was in v5.8), DUID (hex) and IAID are used instead. After upgrade MAC addresses will be converted to DUIDs automatically, but due to unknown DUID type and unknown IAID, they should be further updated by user;
General
Sub-menu: /ipv6 dhcp-server
This sub menu lists and allows to configure DHCP-PD servers.
Properties
| Property | Description |
|---|---|
| address-pool (enum | static-only; Default: static-only) | IPv6 pool, from which to take IPv6 prefix for the clients. |
| authoritative (after-10sec-delay | after-2sec-delay | yes | no; Default: after-2sec-delay) | Whether the DHCP server is the only one DHCP server for the network:
|
| binding-script (string; Default: ) | Script that will be executed after binding is assigned or de-assigned. Internal "global" variables that can be used in the script:
|
| delay-threshold (time | none; Default: none) | If secs field in DHCP packet is smaller than delay-threshold, then this packet is ignored. If set to none - there is no threshold (all DHCP packets are processed) |
| disabled (yes | no; Default: no) | Whether DHCP-PD server participate in prefix assignment process. |
| interface (string; Default: ) | Interface on which server will be running. |
| lease-time (time; Default: 3d) | The time that a client may use the assigned address. The client will try to renew this address after a half of this time and will request a new address after time limit expires. |
| name (string; Default: ) | Reference name |
Read-only Properties
| Property | Description |
|---|---|
| dynamic (yes | no) | |
| invalid (yes | no) |
Bindings
Sub-menu: /ipv6 dhcp-server binding
DUID is used only for dynamic bindings, so if it changes then client will receive different prefix than previously.
| Property | Description |
|---|---|
| address (IPv6 prefix; Default: ) | IPv6 prefix that will be assigned to the client |
| allow-dual-stack-queue (yes | no; Default: yes) | Creates a single simple queue entry for both IPv4 and IPv6 addresses, uses the MAC address and DUID for identification. Requires IPv4 DHCP Server to have this option enabled as well to work properly. |
| comment (string; Default: ) | Short description of an item. |
| disabled (yes | no; Default: no) | Whether item is disabled |
| dhcp-option (string; Default: ) | Add additional DHCP options from option list. |
| dhcp-option-set (string; Default: ) | Add additional set of DHCP options. |
| life-time (time; Default: 3d) | Time period after which binding expires/ |
| duid (hex string; Default: ) | DUID value. Should be specified only in hexadecimal format. |
| iaid (integer [0..4294967295]; Default: ) | Identity Association Identifier, part of the Client ID. |
| prefix-pool (string; Default: ) | Prefix pool that is being advertised to the DHCPv6 Client. |
| rate-limit (integer[/integer] [integer[/integer] [integer[/integer] [integer[/integer]]]]; Default: ) | Adds a dynamic simple queue to limit IP's bandwidth to a specified rate. Requires the lease to be static. Format is: rx-rate[/tx-rate] [rx-burst-rate[/tx-burst-rate] [rx-burst-threshold[/tx-burst-threshold] [rx-burst-time[/tx-burst-time]]]]. 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 is used as burst thresholds. If both rx-burst-time and tx-burst-time are not specified, 1s is used as default. |
| server (string | all; Default: all) | Name of the server. If set to all, then binding applies to all created DHCP-PD servers. |
Read-only properties
| Property | Description |
|---|---|
| dynamic (yes | no) | Whether item is dynamically created. |
| expires-after (time) | Time period after which binding expires. |
| last-seen (time) | Time period since client was last seen. |
| status (waiting | offered | bound) | Three status vales are possible:
|
For example, dynamically assigned /62 prefix
[admin@RB493G] /ipv6 dhcp-server binding> print detail
Flags: X - disabled, D - dynamic
0 D address=2a02:610:7501:ff00::/62 duid="1605fcb400241d1781f7" iaid=0
server=local-dhcp life-time=3d status=bound expires-after=2d23h40m10s
last-seen=19m50s
1 D address=2a02:610:7501:ff04::/62 duid="0019d1393535" iaid=2
server=local-dhcp life-time=3d status=bound expires-after=2d23h43m47s
last-seen=16m13s
Menu specific commands
| Property | Description |
|---|---|
| make-static () | Set dynamic binding as static. |
Rate limiting
It is possible to set a bandwidth to a specific IPv6 address by using DHCPv6 bindings. This can be done by setting a rate limit on the DHCPv6 binding itself, by doing this a dynamic simple queue rule will be added for the IPv6 address that corresponds to the DHCPv6 binding. By using the rate-limit parameter you can conveniently limit a user's bandwidth.
Note: For any queues to work properly, the traffic must not be FastTracked, make sure your Firewall does not FastTrack traffic that you want to limit.
First, make the DHCPv6 binding static, otherwise it will not be possible to set a rate limit to a DHCPv6 binding:
[admin@MikroTik] > /ipv6 dhcp-server binding print Flags: X - disabled, D - dynamic # ADDRESS DUID SERVER STATUS 0 D fdb4:4de7:a3f8:418c::/66 0x6c3b6b7c413e DHCPv6_Server bound [admin@MikroTik] > /ipv6 dhcp-server binding make-static 0 [admin@MikroTik] > /ipv6 dhcp-server binding print Flags: X - disabled, D - dynamic # ADDRESS DUID SERVER STATUS 0 fdb4:4de7:a3f8:418c::/66 0x6c3b6b7c413e DHCPv6_Server bound
Then you need can set a rate to a DHCPv6 binding that will create a new dynamic simple queue entry:
[admin@MikroTik] > /ipv6 dhcp-server binding set 0 rate-limit=10M/10
[admin@MikroTik] > /queue simple print
Flags: X - disabled, I - invalid, D - dynamic
0 D name="dhcp<6c3b6b7c413e fdb4:4de7:a3f8:418c::/66>" target=fdb4:4de7:a3f8:418c::/66 parent=none packet-marks="" priority=8/8 queue=default-small/default-small limit-at=10M/10M max-limit=10M/10M burst-limit=0/0 burst-threshold=0/0
burst-time=0s/0s bucket-size=0.1/0.1
Note: By default allow-dual-stack-queue is enabled, this will add a single dynamic simple queue entry for both DCHPv6 binding and DHCPv4 lease, without this option enabled separate dynamic simple queue entries will be added for IPv6 and IPv4.
If allow-dual-stack-queue is enabled, then a single dynamic simple queue entry will be created containing both IPv4 and IPv6 addresses:
[admin@MikroTik] > /queue simple print
Flags: X - disabled, I - invalid, D - dynamic
0 D name="dhcp-ds<6C:3B:6B:7C:41:3E>" target=192.168.1.200/32,fdb4:4de7:a3f8:418c::/66 parent=none packet-marks="" priority=8/8 queue=default-small/default-small limit-at=10M/10M max-limit=10M/10M burst-limit=0/0 burst-threshold=0/0
burst-time=0s/0s bucket-size=0.1/0.1
RADIUS Support
Since RouterOS v6.43rc56 it is possible to use RADIUS to assign a rate-limit per DHCPv6 binding, to do so you need to pass the Mikrotik-Rate-Limit attribute from your RADIUS Server for your DHCPv6 binding. To achieve this you first need to set your DHCPv6 Server to use RADIUS for assigning bindings. Below is an example how to set it up:
/radius add address=10.0.0.1 secret=VERYsecret123 service=dhcp /ipv6 dhcp-server set dhcp1 use-radius=yes
After that you need to tell your RADIUS Server to pass the Mikrotik-Rate-Limit attribute. In case you are using FreeRADIUS with MySQL, then you need to add appropriate entries into radcheck and radreply tables for a MAC address, that is being used for your DHCPv6 Client. Below is an example for table entries:
INSERT INTO `radcheck` (`username`, `attribute`, `op`, `value`) VALUES
('000c4200d464', 'Auth-Type', ':=', 'Accept'),
INSERT INTO `radreply` (`username`, `attribute`, `op`, `value`) VALUES
('000c4200d464', 'Delegated-IPv6-Prefix', '=', 'fdb4:4de7:a3f8:418c::/66'),
('000c4200d464', 'Mikrotik-Rate-Limit', '=', '10M');
Note: By default allow-dual-stack-queue is enabled and will add a single dynamic queue entry if the MAC address from the IPv4 lease (or DUID, if the DHCPv4 Client supports Node-specific Client Identifiers from RFC4361), but DUID from DHCPv6 Client is not always based on the MAC address from the interface on which the DHCPv6 Client is running on, DUID is generated on per-device basis. For this reason a single dynamic queue entry might not be created, separate dynamic queue entries might be created instead.
Configuration Examples
Enabling IPv6 Prefix delegation
Lets consider that we already have running DHCP server.
To enable IPv6 prefix delegation, first we need to create address pool
/ipv6 pool add name=myPool prefix=2001:db8:7501::/60 prefix-length=62
Notice that prefix-length is 62 bits, it means that clients will receive /62 prefixes from the /60 pool.
Next step is to enable DHCP-PD.
/ipv6 dhcp-server add name=myServer address-pool=myPool interface=local
To test our server we will set up wide-dhcpv6 on ubuntu machine:
- install wide-dhcpv6-client
- edit "/etc/wide-dhcpv6/dhcp6c.conf" as above
Note: You can use also RouterOS as DHCP-PD client. Read more >>
interface eth2{
send ia-pd 0;
};
id-assoc pd {
prefix-interface eth3{
sla-id 1;
sla-len 2;
};
};
- Run DHCP-PD client
sudo dhcp6c -d -D -f eth2
- Verify that prefix was added to eth3
mrz@bumba:/media/aaa$ ip -6 addr
..
2: eth3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qlen 1000
inet6 2001:db8:7501:1:200:ff:fe00:0/64 scope global
valid_lft forever preferred_lft forever
inet6 fe80::224:1dff:fe17:81f7/64 scope link
valid_lft forever preferred_lft forever
- You can make binding to specific client static, so that it always receives the same prefix
[admin@RB493G] /ipv6 dhcp-server binding> print Flags: X - disabled, D - dynamic # ADDRESS DU IAID SER.. STATUS 0 D 2001:db8:7501:1::/62 16 0 loc.. bound [admin@RB493G] /ipv6 dhcp-server binding> make-static 0
- DHCP-PD also installs route to assigned prefix into IPv6 routing table
[admin@RB493G] /ipv6 route> print Flags: X - disabled, A - active, D - dynamic, C - connect, S - static, r - rip, o - ospf, b - bgp, U - unreachable # DST-ADDRESS GATEWAY DISTANCE ... 2 ADS 2001:db8:7501:1::/62 fe80::224:1dff:fe17:8... 1
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