NAME

        SV_RFC1123_6_1_3_3_Retrans_control - Retransmission control

VERIFICATION POINTS

        Verify that a NUT implements retransmission controls.

The resolver MUST implement retransmission controls to insure that it does not waste communication bandwidth, and MUST impose finite bounds on the resources consumed to respond to a single request.

While local limits on the number of times a resolver will retransmit a particular query to a particular name server address are essential, the resolver should have a global per-request counter to limit work on a single request.

TARGET

        Caching Server

SYNOPSIS

	SV_RFC1123_6_1_3_3_Retrans_control.seq [-tooloption ...]: KOI tool option
	See also DNSConfig.pm

INITIALIZATION

Network Topology

                                 . domain                 org domain               example.org domain
        AP Server1 (TN)          DNS Server2              DNS Server3              DNS Server4
          |A.example.org           |A.ROOT.NET              |NS3.example.org         |NS4.example.org
          |3ffe:501:ffff:101::10   |3ffe:501:ffff:101::20   |3ffe:501:ffff:101::30   |3ffe:501:ffff:101::40 
          |192.168.1.10            |192.168.1.20            |192.168.1.30            |192.168.1.40
          |                        |                        |                        |
Net-y   --+--------+---------------+------------------------+------------------------+-- 3ffe:501:ffff:101::/64
                   |                                                                     192.168.1/24
                   |
                   |
                 Router (TN)
                   |3ffe:501:ffff:100::1
                   |192.168.0.1
                   |
                   |
                   |
Net-z   --+--------+-----------------+-------- 3ffe:501:ffff:100::/64
          |                          |          192.168.0/24
          |                          |
        DNS Server1 (NUT)          DNS Client1 (TN)
           3ffe:501:ffff:100::XXXX    3ffe:501:ffff:100::20 
           192.168.0.10               192.168.0.20
	

	XXXX: EUI64

Setup

Set the DNS Server1's (NUT) address as above mentioned Network Topology.

Configure the Server1's (NUT) zone file to response query from TN.

Example of root server list:

For IPv4:

.                       3600000         IN      NS      A.ROOT.NET.
A.ROOT.NET.             3600000                 A       192.168.1.20

For IPv6:

.                       3600000         IN      NS      A.ROOT.NET.
A.ROOT.NET.             3600000                 AAAA    3ffe:501:ffff:101::20

Example of example.com zone file:

$TTL    86400           ; TTL of 1 day
@ IN SOA NS1.example.com. root.example.com. (
	2005081600	; serial
	3600		; refresh every 1 hr
	900		; retry every 15 min
	604800		; expire after a week
	3600		; Minimum TTL of a 1 hr
)
;
	IN	NS	NS1.example.com.
NS1	IN	A	192.168.0.10
;

TEST PROCEDURE

        This test sequence is following.

                                                                    <-------------- TN --------------->

    DNS Client1 (TN)             DNS Server1 (NUT)                  DNS Server2 DNS Server3 DNS Server4
        |                              |                                 |           |           |
        |----------------------------->|                                 |           |           |
        | 1. Send standard query       |                                 |           |           |
        |  QNAME=A.example.org         |                                 |           |           |
        |  QTYPE=A                     |                                 |           |           |
        |                              |                                 |           |           |
        |                              |-------------------------------->|           |           |
        |                              | 2. Recv standard query          |           |           |
        |                              |  QNAME=A.example.org            |           |           |
        |                              |  QTYPE=A                        |           |           |
        |                              |                                 |           |           |
        |                              |<--------------------------------|           |           |
        |                              | 3. Send standard query response |           |           |
        |                              |  QNAME=A.example.org            |           |           |
        |                              |  QTYPE=A                        |           |           |
        |                              |  AUTHORITY Name=org             |           |           |
        |                              |  AUTHORITY Name Server          |           |           |
        |                              |            =NS3.example.org     |           |           |
        |                              |  ADDITIONAL Name                |           |           |
        |                              |            =NS3.example.org     |           |           |
        |                              |  ADDITIONAL Address             |           |           |
        |                              |            =192.168.1.30        |           |           |
        |                              |                                 |           |           |
        |                              |                                 v           |           |
        |                              |                                             |           |
        |                              |-------------------------------------------->|           |
        |                              |             4. Recv standard query          |           |
        |                              |              QNAME=A.example.org            |           |
        |                              |              QTYPE=A                        |           |
        |                              |                                             |           |
        |                              |<--------------------------------------------|           |
        |                              |             5. Send standard query response |           |
        |                              |              QNAME=A.example.org            |           |
        |                              |              QTYPE=A                        |           |
        |                              |              AUTHORITY Name=example.org     |           |
        |                              |              AUTHORITY Name Server          |           |
        |                              |                     = NS4.example.org       |           |
        |                              |              ADDITIONAL Name                |           |
        |                              |                     = NS4.example.org       |           |
        |                              |              ADDITIONAL Address             |           |
        |                              |                     = 192.168.1.40          |           |
        |                              |                                             |           |
        |                              |                                             v           |
        |                              |                                                         |
        |                              |-------------------------------------------------------->|
        |                              |                          6. Send standard query         |
        |                              |                           QNAME=A.example.org           |
        |                              |                           QTYPE=A                       |
        |                              |                                                         |
        //                             //                                                        //
        |                              |                                                         |
        |                              |-------------------------------------------------------->|
        |                              |                          N. Send standard query         |
        |                              |                           QNAME=A.example.org           |
        |                              |                           QTYPE=A                       |
        |                              |                                                         |
        |                              |-----------------------------------------------------> X |
        |                              |                          N+1. Send standard query       |
        |                              |                           QNAME=A.example.org           |
        |                              |                           QTYPE=A                       |
        |                              |                                                         |
        |                              |                                                         |
        v                              v                                                         v

        1. TN send standard query QNAME=A.example.org, QTYPE=A to NUT.
        2. NUT transmits standard query to DNS Server2 (TN: root name server) (Judgment *2)
        3. TN send query response to NUT w/ AUTHORITY Name=org, AUTHORITY Name Server=NS3.example.org.
        4. NUT transmits standard query QNAME=A.example.org, QTYPE=A to DNS Server3 (TN: NS3.example.org) (Judgment *4)
        5. TN send query response to NUT w/ AUTHORITY Name=example.org, AUTHORITY Name Server=NS4.example.org.
        6. NUT transmits standard query QNAME=A.example.org, QTYPE=A to DNS Server4 (TN: NS4.example.org) (Judgment *6)
        N. NUT transmits standard query QNAME=A.example.org, QTYPE=A to DNS Server4 (TN: NS4.example.org) (Judgment *N) 
        N+1. NUT transmits standard query QNAME=A.example.org, QTYPE=A to DNS Server4 (TN: NS4.example.org) (Judgment *N+1) 
        *N means that number of retransmission.

Packet Description

1st packet.

Standard query from DNS Client1 (TN) to Server1 (NUT)
IP Header	Source Address	CL1_NETZ
IP Header	Destination Address	NUT_NETZ
UDP Header	Src Port	2000
UDP Header	Dst Port	53
DNS Header	ID	0x1000
	QR	0
	OPCODE	0
	AA	0
	TC	0
	RD	1
	RA	0
	Z	0
	RCODE	0
	QDCOUNT	1
	ANCOUNT	0
	NSCOUNT	0
	ARCOUNT	0
DNS Question section	QNAME	A.example.org
	QTYPE	A (0x0001)
	QCLASS	IN (0x0001)

2nd packet.

Standard query from DNS Server1 (NUT) to Server2 (TN)
IP Header	Source Address	NUT_NETZ
IP Header	Destination Address	SV2_NETY
UDP Header	Src Port	ANY
UDP Header	Dst Port	53
DNS Header	ID	ANY
	QR	0
	OPCODE	0
	AA	ANY
	TC	0
	RD	0
	RA	ANY
	Z	ANY
	RCODE	ANY
	QDCOUNT	1
	ANCOUNT	0
	NSCOUNT	0
	ARCOUNT	ANY
DNS Question section	QNAME	A.example.org
	QTYPE	A (0x0001)
	QCLASS	IN (0x0001)

3rd packet.

Standard query response from DNS Server2 (TN) to Server1 (NUT)
IP Header	Source Address	SV2_NETY
IP Header	Destination Address	NUT_NETZ
UDP Header	Src Port	53
UDP Header	Dst Port	Value that NUT uses
DNS Header	ID	Value that NUT uses
	QR	1
	OPCODE	0
	AA	0
	TC	0
	RD	0
	RA	0
	Z	0
	RCODE	0
	QDCOUNT	1
	ANCOUNT	0
	NSCOUNT	1
	ARCOUNT	1
DNS Question section	QNAME	A.example.org
	QTYPE	A (0x0001)
	QCLASS	IN (0x0001)
DNS Authority section	NAME	org (Pointer 0xC016)
	TYPE	NS (0x0002)
	CLASS	IN (0x0001)
	TTL	1 day (86400)
	RDLENGTH	6
	NSDNAME	NS3.example.org (NS3 + Pointer 0xC00E)
DNS Additional section	NAME	NS3.example.org (Pointer 0xC02B)
	TYPE	A (0x0001)
	CLASS	IN (0x0001)
	TTL	1 day (86400)
	RDLENGTH	4
	ADDRESS	192.168.1.30

4th packet.

Standard query from DNS Server1 (NUT) to Server3 (TN)
IP Header	Source Address	NUT_NETZ
IP Header	Destination Address	SV3_NETY
UDP Header	Src Port	ANY
UDP Header	Dst Port	53
DNS Header	ID	ANY
	QR	0
	OPCODE	0
	AA	ANY
	TC	0
	RD	0
	RA	ANY
	Z	ANY
	RCODE	ANY
	QDCOUNT	1
	ANCOUNT	0
	NSCOUNT	0
	ARCOUNT	ANY
DNS Question section	QNAME	A.example.org
	QTYPE	A (0x0001)
	QCLASS	IN (0x0001)

5th packet.

Standard query response from DNS Server3 (TN) to Server1 (NUT)
IP Header	Source Address	SV3_NETY
IP Header	Destination Address	NUT_NETZ
UDP Header	Src Port	Value that NUT uses
UDP Header	Dst Port	53
DNS Header	ID	Value that NUT uses
	QR	1
	OPCODE	0
	AA	0
	TC	0
	RD	0
	RA	0
	Z	0
	RCODE	0
	QDCOUNT	1
	ANCOUNT	0
	NSCOUNT	1
	ARCOUNT	1
DNS Question section	QNAME	A.example.org
	QTYPE	A (0x0001)
	QCLASS	IN (0x0001)
DNS Authority section	NAME	example.org (Pointer 0xC00E)
	TYPE	NS (0x0002)
	CLASS	IN (0x0001)
	TTL	1 day (86400)
	RDLENGTH	6
	NSDNAME	NS4.example.org (NS4 + Pointer 0xC00E)
DNS Additional section	NAME	NS4.example.org (Pointer 0xC02B)
	TYPE	A (0x0001)
	CLASS	IN (0x0001)
	TTL	1 day (86400)
	RDLENGTH	4
	ADDRESS	192.168.1.40

6th packet.

Standard query from DNS Server1 (NUT) to Server4 (TN)
IP Header	Source Address	NUT_NETZ
IP Header	Destination Address	SV4_NETY
UDP Header	Src Port	ANY
UDP Header	Dst Port	53
DNS Header	ID	ANY
	QR	0
	OPCODE	0
	AA	ANY
	TC	0
	RD	0
	RA	ANY
	Z	ANY
	RCODE	ANY
	QDCOUNT	1
	ANCOUNT	0
	NSCOUNT	0
	ARCOUNT	ANY
DNS Question section	QNAME	A.example.org
	QTYPE	A (0x0001)
	QCLASS	IN (0x0001)

N th packet.

Standard query from DNS Server1 (NUT) to Server4 (TN)
IP Header	Source Address	NUT_NETZ
IP Header	Destination Address	SV4_NETY
UDP Header	Src Port	ANY
UDP Header	Dst Port	53
DNS Header	ID	ANY
	QR	0
	OPCODE	0
	AA	ANY
	TC	0
	RD	0
	RA	ANY
	Z	ANY
	RCODE	ANY
	QDCOUNT	1
	ANCOUNT	0
	NSCOUNT	0
	ARCOUNT	ANY
DNS Question section	QNAME	A.example.org
	QTYPE	A (0x0001)
	QCLASS	IN (0x0001)

Exp.

NUT_NETZ	DNS Server1's (NUT) Net-z address
CL1_NETZ	DNS Client1's (TN) Net-z address
SV2_NETY	DNS Server2's (TN) Net-y address
SV3_NETY	DNS Server3's (TN) Net-y address
SV4_NETY	DNS Server4's (TN) Net-y address

JUDGMENT

        2. Received standard query including QNAME=A.example.org, QTYPE=A.
        4. Received standard query including QNAME=A.example.org, QTYPE=A.
        6. Received standard query including QNAME=A.example.org, QTYPE=A.
        N. Received standard query including QNAME=A.example.org, QTYPE=A.
        N+1. Not received standard query.

TERMINATION

        None

REFERENCE

        RFC1035 DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION
        7.1. Transforming a user request into a query

        RFC1123 Requirements for internet Hosts -- Application and Support
        6.1.3.3  Efficient Resource Usage