Chapter 23. summary of tcp/ip networking


After speaking a great deal about addressing in IPv6, anybody still

here will hope that you have a correct way to abstract all

these lengthy & ugly IPv6 addresses with a few nice hostnames

as you can perform in IPv4, not to mention there’s.

Hostname to Ip resolving in IPv4 is generally completed in

1 of 3 ways: utilizing a simple table in

/etc/hosts, by

while using Network Information Service (NIS, formerly YP)

or through the Website Name System (DNS).

At this moment, NIS/NIS+ over IPv6 is presently only

on Solaris 8, for database contents and

transport, utilizing a RPC extension.

Getting an easy addressname map like

/etc/hosts is

supported in most IPv6 stacks. Using the KAME implementation

utilized in NetBSD, /etc/hosts contains

IPv6 addresses

in addition to IPv4 addresses. An easy example may be the

“localhost” entry within the default NetBSD installation:

127…1 localhost

::1 localhost

For DNS, there aren’t any essentially new concepts. IPv6

name resolving is performed with AAAA records that – because the

name implies – indicate a business that’s four occasions the

size a b record. The AAAA record requires a hostname on

the left side, just like A does, as well as on the best side

likely to IPv6 address, e.g.

noon IN AAAA 3ffe:400:430:2:240:95ff:fe40:4385

For reverse resolving, IPv4 uses the zone,

and below it writes the bytes (in decimal) in

reversed order, i.e. higher bytes tend to be more

right. For IPv6 this really is similar, that hex digits

representing 4 bits are utilized rather of decimal figures,

and also the resource records will also be within different


So to achieve the reverse resolving for that above host, you

would put in your /etc/named.conf

something similar to:

Chapter 23. summary of tcp/ip networking reverse resolving

zone “.3.4….4..e.f.f.3.IP6.INT”

as well as in the zone file db.reverse you place (aside from the usual

records like SOA and NS):

Chapter 23. summary of tcp/ip networking the other, beginning… IN PTR

The address is reversed here, and written lower one hex

digit following the other, beginning using the least significant

(rightmost) one, separating the hex digits with dots, as

usual in zone files.

One factor to notice when establishing DNS for IPv6 would be to take

proper care of the DNS software version being used. BIND 8.x does

understand AAAA records, but it doesn’t offer name

resolving via IPv6. You’ll need BIND 9.x for your. Beyond

that, BIND 9.x supports numerous resource records that

are presently being discussed although not formally

introduced yet. Probably the most noticeable one this is actually the A6

record which enables simpler provider/prefix altering.

To summarize, this spoken concerning the technical

variations between IPv4 and IPv6 for addressing and name

resolving. Some details like IP header options, QoS and

flows were deliberately overlooked not to get this to

document more complicated than necessary.


What is TCP/IP?