[Linux-bruxelles] problème de serveur web avec un modem SpeedTouch 510 (ip dynamique, DNS chez dyndns.org)
Rusinsky Stanislas Herman W. A.
rusinskystanislas at yahoo.fr
Jeu 5 Fév 15:13:41 CET 2004
> renseigne toi avant de lancer n'importe quoi
lis avant de lancer un flamebate,
> ben si t'arrive pas a savoir avec ipv4 je voie pas ce que IPV6 peut faire de
> mieux car je sais pas si t'es au courant mais IPV6 est simplement et
> Uniquement une systeme d'adressage te permettant d'avoir un nombre plus
> important de machine connecter
> Mais en rien ne changera le fonctionnement d'une connection net a travers un
> PS: que tu soit avec le modem toto ou tata rien ne chnage a part ton pilote de
> pheripherique ;-)
le pilote de périph n'a rien à voir dans l'histoire, je n'ai jamais
parlé de ma carte ethernet :P
pour l'IPv6 voici ma réponse:
The design philosophy of IPv6 is a scalable protocol that provides a
large address space with a simple structure, an original end-to-end
environment, a NAT-free network, fast processing, and many features
needed by current and future applications. Migrating from IPv4 to IPv6,
and IPv6 deployment should not be expensive. IPv6 should inter-operate
with IPv4 and provide tools and mechanisms needed by hosts running
different IP versions to communicate with each other, and to enable
applications to work with both IP versions.
IPv6 was designed with enhanced features compared to IPv4. Its major
Large Address Space
IPv6 provides a 128-bit address field. This extended address space is
very essential, as IP addresses will be assigned to mobile phones, home
appliances, motor vehicles, and other equipment. In addition, with such
a huge address space, we can create multi-level hierarchies of
addresses, simplifying routing problems — requiring simpler routing
algorithms and less space needed for routing tables.
New Types of Addresses
IPv6 introduces the concept of scoped addresses and defines three types
of addresses: unicast (global, link local, site local), multicast, and
An IPv6 unicast address identifies a single interface. A packet
sent to a unicast address is delivered to the interface identified by
that address. Three types of unicast addresses exist:
1. A global unicast address is used for point-to-point
2. A link local unicast address allows packets to traverse on only
one link or segment. Routers will not forward packets with link local
3. A site local unicast address limits the scope of packet
delivery to your intranet. The edge router connecting your internal
network to the external network will not forward packets with site local
unicast addresses to the external network.
An IPv6 multicast address delivers copies of one source packet to
recipients. In the IPv6 multicast address, you can specify multicast
scope, which can be node-local, link-local, site-local, or global.
An IPv6 anycast address identifies a set of interfaces typically
belonging to different nodes. A packet sent to an anycast address is
delivered to one of the interfaces identified by that address. Anycast
differs from multicast in that it delivers a message to any one of the
nodes in a group. When one node — often the nearest node in the group —
receives the message, anycast is finished.
IPv6 provides hosts with the ability to configure themselves
automatically without the use of a stateful configuration protocol. A
host can also use router discovery to determine the addresses of
routers, additional addresses, and other configuration parameters. This
feature allows hosts to discover automatically all the information they
need to connect to the Internet, without any human intervention.
New Streamlined Header Format
IPv6 has a new 40-bytes header (as shown in Figure 1) with the following
* Version, 4 bits that identify the version of the Internet
* Traffic class, 8 bits that identify different classes or
* Flow label, 20 bits used by a source node to identify packets that
belong to the same flow.
* Payload length, 16 bits containing the length of the IPv6 payload.
* Next header, 8 bits that indicate to the router which extension
header to expect next. If there are no more extension headers, the next
header field indicates the upper layer header.
* Hop limit, indicating the maximum number of hops allowed.
* Source address, 128 bits containing the address of the source node
sending the packet.
* Destination address, 128 bits containing the final destination
node address for the packet.
Figure 1. The IPv6 header.
In addition, IPv6 is much more flexible in its support of options
through extension headers. Extension headers encode optional
Internet-layer information. They are placed between the IPv6 header and
the upper layer header in a packet and are chained together using the
next header field in the IPv6 header. There are six different extension
headers: Hop-by-hop Options, Destination Options, Routing, Fragment,
Authentication, and Encapsulated Security. The next header field
indicates to the router which extension header to expect next. If there
are no more extension headers, the next header field indicates the
upper-layer header (TCP header, UDP header, ICMPv6 header, an
encapsulated IP packet, or other items).
Better Network Management
IPv6 provides enhancements that allow better network management such as
network renumbering, which make it simpler to move a whole network to a
new ISP by reconfiguring the router with the new routing prefix from the
Improved Mobility Support
Mobility support in IPv6 allows transparent routing of IPv6 packets to
mobile nodes, taking advantage of the design of a new version of IP.
Support for IPsec
The IETF has mandated support for Internet Protocol Security (Ipsec)
with IPv6 so it will not be an optional extension, as was the case with
The IETF has specified two approaches, integrated services and
differentiated services, to provide guaranteed and selectable Quality of
Service (QoS) over the Internet. In addition, IPv6 provides flow labels
that can be used to provide QoS by identifying the packets as belonging
to a flow. These labels can be used in conjunction with a hop-by-hop
routing extension header (allowing predefined routes) and the priority
field (allowing for QoS). The flow label also serves as a key in the
router cache to reduce the amount of processing. When a router first
receives a datagram, it can cache the flow label and next hop so as to
save time when the next datagram arrives with the same flow label. This
technique reduces router processing time considerably.
As a result, IPv6 is feature-rich, fixing many of the problems of IPv4
and adding much new functionality. To read more on these features,
please refer to my IPv6 Essentials article.
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