DNS

DNS

Warning

Work in progress.

Automated hiearchy

There are four levels.

Connectivity:

Level	Name	Peer	Parent
1	Client	None	dns_l2_cluster
2	Caching Server	?	asn
3	AS Server	?	root
4	Root	None	None

Records:

Level	Responsibility o
1	None
2	Caching for clients
3	Authoritative for dns_l2_cluster
4	Root - announces relevant l3

dns_l2_cluster is PoP if set, if not is asn

#TODO: allow levels to be selected:

Levels	Meaning
1	NA
2	clients (1) connect to root (2)
3	clients (1) connect to as (3), as to root (4)
4	full, as above

AutoNetkit.algorithms.dns.allocate_dns_servers(network)

Allocates DNS according to rules defined above

TODO: allow 3 level (ie no pop caching, clients connect to AS server) TODO: make DNS servers standalone rather that co-hosted with router

TODO: note set dns level on dns graph, but ibgp level on physical graph - inconsistent!

AutoNetkit.algorithms.dns.dns_servers(network)

Servers that have DNS level > 1

AutoNetkit.algorithms.dns.dns_auth_servers(network)

Servers that have auth children

AutoNetkit.algorithms.dns.dns_clients(network)

Devices that have DNS level == 1

AutoNetkit.algorithms.dns.reverse_subnet(ip, prefixlen)

Returns reverse address for given IP Address

• w.x.y.z/prefixlen
• prefixlen >= 24 -> return z
• 24 >= prefixlen >= 16 -> return z.y
• 16 >= prefixlen >= 8 -> return z.y.w
• 8 >= prefixlen -> return z.y.x.w

>>> reverse_subnet(IPAddress("10.0.0.22"), 16)
'22.0'
>>> reverse_subnet(IPAddress("10.0.0.21"), 16)
'21.0'
>>> reverse_subnet(IPAddress("10.0.0.129"), 16)
'129.0'
>>> reverse_subnet(IPAddress("1.2.3.4"), 5)
'4.3.2.1'
>>> reverse_subnet(IPAddress("1.2.3.4"), 15)
'4.3.2'
>>> reverse_subnet(IPAddress("1.2.3.4"), 20)
'4.3'
>>> reverse_subnet(IPAddress("1.2.3.4"), 26)
'4'

AutoNetkit.algorithms.dns.rev_dns_identifier(subnet)

Returns Identifier part of subnet for use in reverse dns identification.

>>> rev_dns_identifier(IPNetwork("10.1.2.3/8"))
'0.0.10.in-addr.arpa.'

>>> rev_dns_identifier(IPNetwork("172.16.1.2/16"))
'16.172.in-addr.arpa.'

>>> rev_dns_identifier(IPNetwork("192.168.0.1/24"))
'0.0.168.192.in-addr.arpa.'

Can only handle classful addreses, expect nothing if prefixlen is not divisible by 8 >>> rev_dns_identifier(IPNetwork(“192.168.0.1/22”))