Datasheet

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DNS can do more than just resolve host names. The name server also

knows which host is receiving e-mails for an entire domain — the mail ex-

changer (MX).

For your machine to resolve an IP address, it must know about at least one

name server and its IP address. Easily specify such a name server with

the help of YaST. If you have a modem dial-up connection, you may not

need to conﬁgure a name server manually at all. The dial-up protocol pro-

vides the name server address as the connection is made. The conﬁgura-

tion of name server access with SUSE LINUX is described in Section 21.7 on

page 458.

The protocol whois is closely related to DNS. With this program, quickly

ﬁnd out who is responsible for any given domain.

21.2 IPv6 — The Next Generation

Internet

Note

S/390, zSeries: IPv6 Support

IPv6 is not supported by the CTC and IUCV network connec-

tions of the IBM S/390 and zSeries hardware.

Note

Due to the emergence of the WWW (World Wide Web), the Internet has

experienced explosive growth with an increasing number of computers

communicating via TCP/IP in the last ten years. Since Tim Berners-Lee at

CERN (http://public.web.cern.ch) invented the WWW in 1990, the

number of Internet hosts has grown from a few thousand to about a hun-

dred million.

As mentioned, an IP address consists of only 32 bits. Also, quite a few IP

addresses are lost — they cannot be used due to the way in which net-

works are organized. The number of addresses available in your subnet

is the number of bits squared minus two. A subnetwork has, for example,

two, six, or fourteen addresses available. To connect 128 hosts to the In-

ternet, for example, you need a subnetwork with 256 IP addresses, from

which only 254 are usable, because two IP addresses are needed for the

structure of the subnetwork itself: the broadcast and the base network ad-

dress.

422 21.2. IPv6 — The Next Generation Internet