From: Tomek Mrugalski Date: Thu, 13 Feb 2014 19:48:20 +0000 (+0100) Subject: [3322] The guide is now updated (relay override and classification examples) X-Git-Tag: bind10-1.2.0beta1-release~27^2~9 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1158dbada8422f122b7a08b67bdb844a91be26ac;p=thirdparty%2Fkea.git [3322] The guide is now updated (relay override and classification examples) --- diff --git a/doc/guide/bind10-guide.xml b/doc/guide/bind10-guide.xml index b74a1e22f7..4a65ba1b7b 100644 --- a/doc/guide/bind10-guide.xml +++ b/doc/guide/bind10-guide.xml @@ -4600,6 +4600,75 @@ Dhcp4/subnet4 [] list (default) +
+ Using specific relay for a subnet + + The relay has to have an interface connected to the link on which + the clients are being configured. Typically the relay has an IPv4 + address configured on that interface that belongs to the subnet that + the server will assign addresses from. In such typical case, the + server is able to use IPv4 address inserted by the relay (in GIADDR + field of the DHCPv4 packet) to select appropriate subnet. + + + However, that is not always the case. In certain uncommon, but + valid deployments, the relay address may not match the subnet. This + usually means that there is more than one subnet allocated for a given + link. Two most common examples where this is the case are long lasting + network renumbering (where both old and new address space is still being + used) and a cable network. In a cable network both cable modems and the + devices behind them are physically connected to the same link, yet + they use distinct addressing. In such case, the DHCPv4 server needs + additional information (IPv4 address of the relay) to properly select + an appropriate subnet. + + + The following example assumes that there is a subnet 192.0.2.0/24 + that is accessible via relay that uses 10.0.0.1 as its IPv4 address. + The server will be able to select this subnet for any incoming packets + that came from a relay that has an address in 192.0.2.0/24 subnet. + It will also select that subnet for a relay with address 10.0.0.1. + +> config add Dhcp4/subnet4 +> config set Dhcp4/subnet4[0]/subnet "192.0.2.0/24" +> config set Dhcp4/subnet4[0]/pool [ "192.0.2.10 - 192.0.2.20" ] +> config set Dhcp4/subnet4[0]/relay/ip-address "10.0.0.1" +> config commit + + +
+ +
+ Segregating IPv4 clients in a cable network + + In certain cases, it is useful to mix relay address information, + introduced in with client + classification, explained in . + One specific example is cable network, where typically modems + get addresses from a different subnet than all devices connected + behind them. + + + Let's assume that there is one CMTS (Cable Modem Termination System) + with one CM MAC (a physical link that modems are connected to). + We want the modems to get addresses from the 10.1.1.0/24 subnet, while + everything connected behind modems should get addresses from another + subnet (192.0.2.0/24). The CMTS that acts as a relay an uses address + 10.1.1.1. The following configuration can serve that configuration: + +> config add Dhcp4/subnet4 +> config set Dhcp4/subnet4[0]/subnet "10.1.1.0/24" +> config set Dhcp4/subnet4[0]/pool [ "10.1.1.2 - 10.1.1.20" ] +> config set Dhcp4/subnet4[0]/client-class "docsis3.0" +> config set Dhcp4/subnet4[0]/relay/ip-address "10.1.1.1" +> config add Dhcp4/subnet4 +> config set Dhcp4/subnet4[1]/subnet "192.0.2.0/24" +> config set Dhcp4/subnet4[1]/pool [ "192.0.2.10 - 192.0.2.20" ] +> config set Dhcp4/subnet4[1]/relay/ip-address "10.1.1.1" +> config commit + +
+
Supported Standards The following standards and draft standards are currently @@ -4691,6 +4760,23 @@ Dhcp4/renew-timer 1000 integer (default)
+ + @@ -5641,6 +5727,78 @@ should include options from the isc option space: +
+ Using specific relay agent for a subnet + + The relay has to have an interface connected to the link on which + the clients are being configured. Typically the relay has a global IPv6 + address configured on that interface that belongs to the subnet that + the server will assign addresses from. In such typical case, the + server is able to use IPv6 address inserted by the relay (in link-addr + field in RELAY-FORW message) to select appropriate subnet. + + + However, that is not always the case. The relay + address may not match the subnet in certain deployments. This + usually means that there is more than one subnet allocated for a given + link. Two most common examples where this is the case are long lasting + network renumbering (where both old and new address space is still being + used) and a cable network. In a cable network both cable modems and the + devices behind them are physically connected to the same link, yet + they use distinct addressing. In such case, the DHCPv6 server needs + additional information (like the value of interface-id option or IPv6 + address inserted in the link-addr field in RELAY-FORW message) to + properly select an appropriate subnet. + + + The following example assumes that there is a subnet 2001:db8:1::/64 + that is accessible via relay that uses 3000::1 as its IPv6 address. + The server will be able to select this subnet for any incoming packets + that came from a relay that has an address in 2001:db8:1::/64 subnet. + It will also select that subnet for a relay with address 3000::1. + +> config add Dhcp6/subnet6 +> config set Dhcp6/subnet6[0]/subnet "2001:db8:1::/64" +> config set Dhcp6/subnet6[0]/pool [ "2001:db8:1::2 - 2001:db8:1::ffff" ] +> config set Dhcp6/subnet6[0]/relay/ip-address "3000::1" +> config commit + + +
+ +
+ Segregating IPv6 clients in a cable network + + In certain cases, it is useful to mix relay address information, + introduced in with client + classification, explained in . + One specific example is cable network, where typically modems + get addresses from a different subnet than all devices connected + behind them. + + + Let's assume that there is one CMTS (Cable Modem Termination System) + with one CM MAC (a physical link that modems are connected to). + We want the modems to get addresses from the 3000::/64 subnet, + while everything connected behind modems should get addresses from + another subnet (2001:db8:1::/64). The CMTS that acts as a relay + an uses address 3000::1. The following configuration can serve + that configuration: + +> config add Dhcp6/subnet6 +> config set Dhcp6/subnet6[0]/subnet "3000::/64" +> config set Dhcp6/subnet6[0]/pool [ "3000::2 - 3000::ffff" ] +> config set Dhcp6/subnet6[0]/client-class "docsis3.0" +> config set Dhcp6/subnet6[0]/relay/ip-address "3000::1" +> config add Dhcp6/subnet6 +> config set Dhcp6/subnet6[1]/subnet "2001:db8:1::/64" +> config set Dhcp6/subnet6[1]/pool [ "2001:db8:1::1 - 2001:db8:1::ffff" ] +> config set Dhcp6/subnet6[1]/relay/ip-address "3000::1" +> config commit + +
+ +
Supported Standards The following standards and draft standards are currently @@ -5712,6 +5870,23 @@ Dhcp6/renew-timer 1000 integer (default)
+ +