Transcript DNS zone suffix option for DHCPv6

DNS zone suffix option for DHCPv6
(draft-yan-dhc-dhcpv6-opt-dnszone-01.txt)
IETF 61 (Washington, DC)
Yinglan Jiang
Renxiang Yan
[email protected]
[email protected]
Alcatel Shanghai Bell
Background
A typical model for IPv6 access network


Prefix delegation from aggregation device to CPE
Router Advertisement from CPE to IPv6 terminals
Terminal
RA
Terminal
CPE
Aggregation
device
IP prefix delegation
Using DHCP
ISP core
network
Terminal
User network
ISP network
From: RFC3633 (IPv6 Prefix Options for DHCPv6)
IPv6 makes it possible for every terminal to become a “server”, it will
be convenient to have a domain name for the terminal.

We should make it easy to configure
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Background (cont.)
Three existing methods to register domain name
Manually add a DNS RR (resource record) into the DNS server
database;
RA-based DNS auto-registration mechanism;

draft-jeong-ipv6-ra-dns-autoconf-01.txt
Using FQDN option, register domain name by DHCP client or
DHCP server;

draft-volz-dhc-dhcpv6-fqdn-00.txt
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When using in access network
Using RA-based method
Terminal
RA
Terminal
CPE
IP prefix delegation
Using DHCP
Aggregation
device
ISP core
network
Terminal
User network
ISP network
Usage

Manually configure a DNS zone suffix in CPE;

CPE advertises DNS information to terminals using RA, terminals perform DNS update.
Disadvantage

Manually configure a DNS zone suffix in CPE require a lot of efforts.
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When using in access network (cont.)
Using FQDN option – method 1
Terminal
Terminal
FQDN
DHCP server
CPE
IP prefix delegation
Using DHCP
Aggregation
device
ISP core
network
Terminal
User network
ISP network
Usage

CPE will work as a DHCP client to request the prefix from aggregation device, and as a
DHCP server to configure an IP address and FQDN to each terminal. Terminal or CPE
performs DNS update.
Disadvantages


DNS zone suffix should be manually configured in the CPE;
Doing DNS update from user side may conflict with the intension of FQDN option.
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When using in access network (cont.)
Using FQDN option – method 2
FQDN
DHCP server
Terminal
Terminal
Terminal
CPE
Aggregation
device
DHCP relay
DHCP relay
User network
ISP core
network
ISP network
Usage

Each terminal requests an unique IPv6 address, along with FQDN from DHCP server in
provider side. Terminal or DHCP server performs DNS update
Disadvantages


Too many terminals will require high performance of DHCP server
CPE and aggregation device should realize DHCP relay
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DNS zone suffix option for DHCPv6
A new method here: DNS zone suffix option for DHCPv6
DNS zone suffix option will provide a method to transfer DNS
zone suffix from DHCP server to DHCP client (typically, a router
used for stateless configuration).
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Definition & Typical operation
Definition
0
1
2
3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
OPTION_DNS_Zone_suffix
|
option-length
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
~
DNS zone suffix
~
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Operation


DHCP client sends a SOLICIT /REQUEST /INFORMATION REQUEST
message to DHCP server
DHCP server sends REPLY message with DNS zone suffix option to
DHCP client.
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Usage of DNS zone suffix option
Terminal
Terminal
DNS zone suffix option
RA
CPE
IP prefix delegation
Using DHCP
Aggregation
device
ISP core
network
Terminal
User network
ISP network
CPE requests IPv6 prefix and DNS zone suffix from aggregation device
CPE transfers DNS information to terminals

Using RA-based DNS auto-registration, OR

Using an embedded DHCPv6 server(stateful/stateless) in CPE.
Terminals perform DNS update with DNS server.
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To conclude
Four methods to register domain name
ID
Method
Applicable to
Reference
1
Manually
Network with few host
-
2
RA-based
Enterprise network
draft-jeong-ipv6-ra-dnsautoconf-01.txt
3
FQDN option
Enterprise network
draft-volz-dhc-dhcpv6fqdn-00.txt
4
DNS suffix option
+ (RA-based,
stateless DHCP or
FQDN option)
IPv6 Access network
Draft-yan-dhc-dhcpv6opt-dnszone-01.txt
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Questions ?
Accepted as WG Item ?
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