Commit 9023c423 authored by Andreas Gustafsson's avatar Andreas Gustafsson
Browse files

minor editing

parent 26a455b8
$Id: ipv6,v 1.1 2000/05/23 22:28:09 explorer Exp $
Currently, there are multiple interesting problems with ipv6
implementations on various platforms. These problems range from not
......@@ -34,7 +33,7 @@ ipv6 easier, by only requiring one socket to be open on a given port.
Later, it was discovered that this was generally a bad idea. For one,
many firewalls will block connection to 1.2.3.4, but will let through
ffff::1.2.3.4. This, of course, is bad. Also, access controll lists
ffff::1.2.3.4. This, of course, is bad. Also, access control lists
written to accept only ipv4 addresses were suddenly ignored unless
they were rewritten to handle the ipv6 mapped addresses as well.
......@@ -43,12 +42,12 @@ UDP, and specific addresses for ipv4 sockets. This causes some
interesting behavior depending on the system implementation of ipv6.
IPV6 Accepts IPV4, Specific IPV4 Addresses Bindings Fail
--------------------------------------------------------
IPV6 Sockets Accept IPV4, Specific IPV4 Addresses Bindings Fail
---------------------------------------------------------------
The only OS which seems to do this is linux. If an ipv6 socket is
bound to the ipv6 wildcard socket, and a specific ipv4 socket is
later bound (say, to 10.2.3.4 port 53) the ipv4 binding will fail.
later bound (say, to 1.2.3.4 port 53) the ipv4 binding will fail.
What this means to bind9 is that the application will log warnings
about being unable to bind to a socket because the address is already
......@@ -59,8 +58,8 @@ The effect is that the config file listen-on directive will not be
respected on these systems.
IPV6 Accepts IPV4, Specific IPV4 Address Bindings Succeed
---------------------------------------------------------
IPV6 Sockets Accept IPV4, Specific IPV4 Address Bindings Succeed
----------------------------------------------------------------
In this case, the system allows opening an ipv6 wildcard address
socket and then binding to a more specific ipv4 address later. An
......@@ -69,19 +68,19 @@ applied.
What this means to bind9 is that the application will respect
listen-on in regards to ipv4 sockets, but it will use mapped ipv6
addresses for any that do not match a listen-on address. This, in
addresses for any that do not match the listen-on list. This, in
effect, makes listen-on useless for these machines as well.
IPV6 Does Not Accept IPV4
-------------------------
IPV6 Sockets Do Not Accept IPV4
-------------------------------
On these systems, opening an IPV6 socket does not implicitly open any
ipv4 sockets. An example of these systems are NetBSD-current with the
latest KAME patch, and other systems which use the latest KAME patches
as their ipv6 implementation.
On these sytems, listen-on is fully functional, as the ipv6 socket
On these systems, listen-on is fully functional, as the ipv6 socket
only accepts ipv6 packets, and the ipv4 sockets will handle the ipv4
packets.
......@@ -94,3 +93,6 @@ RELEVANT RFCs
2553: Basic Socket Interface Extensions for IPv6
draft-ietf-ipngwg-rfc2292bis-01: Advanced Sockets API for IPv6 (draft)
$Id: ipv6,v 1.2 2000/05/23 22:42:00 gson Exp $
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