Manual:IPv6/DHCP Server
Summary
Standards: RFC 3315, RFC 3633
Package: dhcp,ipv6
Starting from v5.9 DHCPv6 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 DHCPv6 servers.
Properties
Property | Description |
---|---|
address-pool (string | static-only; Default: static-only) | IPv6 pool, from which to take IPv6 prefix for the clients. If set to static-only, then only the clients that have a static binding (added in bindings submenu) will be allowed. |
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 DHCPv6 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 |
comment (string; Default: ) | Short description of an item. |
disabled (yes | no; Default: no) | Whether item is disabled |
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: ) | |
server (string | all; Default: all) | Name of the server. If set to all, then binding applies to all created DHCPv6 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@cablefree] /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. |
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 DHCPv6.
/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 RadioOS as DHCPv6-PD client. Read more >>
interface eth2{ send ia-pd 0; }; id-assoc pd { prefix-interface eth3{ sla-id 1; sla-len 2; }; };
- Run DHCPv6 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@cablefree] /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@cablefree] /ipv6 dhcp-server binding> make-static 0
- DHCPv6 also installs route to assigned prefix into IPv6 routing table
[admin@cablefree] /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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