SSH login takes very long time...sometimes

[Rostislav Krasny]

On Mon, 27 Feb 2006 02:49:15 +0900
Hajimu UMEMOTO <ume at freebsd.org> wrote:

> Hi,
> 
> >>>>> On Sun, 26 Feb 2006 17:40:19 +0200
> >>>>> Rostislav Krasny <rosti.bsd at gmail.com> said:
> 
> rosti> It will require to specify a virtual host for each address or to use
> rosti> hostname with multiple addresses only once. Specifying a virtual host by
> rosti> a hostname and registering multiple hostname's addresses in /etc/hosts
> rosti> should not be confusing, IMHO. If the addresses are already registered
> rosti> on DNS, the work is even simpler.
> 
> rosti> Even specifying virtual hosts by addresses should not be confusing,
> rosti> because IPv4-mapped IPv6 address and the IPv4-mapped itself are
> rosti> certainly not the same, although they are mapped each to other. Indeed,
> rosti> someone could want to specify different virtual ftp hosts for IPv4 and
> rosti> mapped to it IPv6 addresses. For example to use different motd, welcome
> rosti> or statfile files.
> 
> Then, you are already confused.
> 
> rosti> When a remote address is an IPv4-mapped IPv6 address, why the local IPv6
> rosti> address must be of the same type and cannot be any regular IPv6 address?
> 
> Because, the connection uses an IPv4 to communicate with each other.
> There is two representation for one IPv4 address; native IPv4 address
> and an IPv4-mapped IPv6 address.  It is thorny thing.

You may be right and I'm confused. I don't have much experience with
IPv6. I just thought that any unicast IPv6 host, even IPv4-mapped IPv6
host, can communicate with any other unicast IPv6 host, including
non-IPv4-mapped IPv6 host. Could you please suggest a good
comprehensive article on the Web about IPv4-mapped IPv6 addresses and
their usage? By the way, why you don't do the address type test in a
daemon mode of ftpd?