Subject: Re: Turning off link-locals?

From: Ian Lister <[email-masked]>
Date: Wed, 22 Jan 2003 22:50:46 +1000 (EST)

On Wed, 22 Jan 2003, John C. Welch wrote:
>Because you have a reason to not want the world to be able to get to your
>printers, so a LL - only device satisfies this need nicely. So they CAN'T
>get global addresses.

OK, that's fine. Not exactly a common case (most people would just filter
printer traffic at the firewall if they didn't want them to be
world-accessible), but let's consider it.

>Now, how do you deal with this case?

Either configure your DHCP server to not assign an address to your
printers (in which case they will fail to acquire an address by any other
means and fall back to IPv4LL, still able to communicate with the other
hosts on the link), or configure the printers to not do DHCP (and only do
IPv4LL). Pretty much the same as how it works now if you don't want your
printers to acquire an IP address at all (perhaps to only do
IPX/AppleTalk/whatever).

Ian

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From: "Christian Huitema" <[email-masked]>
Date: Wed, 22 Jan 2003 08:42:53 -0800

>   | Not really. Adam MacBeth is correct: Windows (including the recent
>   | versions) will first try to get a DHCP address for about 1 minute,
> 
> And one assumes, that should there be lots of complaints about the
time
> that is taking (compared to other things happening in parallel that
> people are waiting for anyway - virus scanners and such), then the
> amount of effort it would take to lower that minute to 10 seconds, or
> something, would not bankrupt Microsoft?    (Ignoring distribution,
> those who want the mod can just fetch a patch).

The purpose of my message was to document what is actually implemented.
I have heard several types of complaints: that the initial set-up takes
too long; that it takes too long to go back to DHCP assigned addresses
once the stack has chosen to use auto-IP; and that the host should keep
an allocated DHCP address even if the DHCP server is momentarily
unavailable when it tries to renew. The "too slow" complaint is mostly
an issue with mobile devices plugging in an ad hoc network; it is not a
big issue in home networks, as most home routers tend to have a DHCP
server anyhow; my preferred solution for mobile hosts in ad hoc networks
would be to just use IPv6.

-- Christian Huitema