Re: Stupid Question maybe?

[Tony Finch <dot () dotat at>]

> On 18 Dec 2018, at 22:30, Joel Halpern <jmh () joelhalpern com> wrote:
>
> History of non-contiguous network masks, as I observed it. [snip]
>
> When we were done, other folks looked at the work (I don't know if the Internet Drafts are still in repositories, but 
> they shoudl be.)  And concluded that while this would work, no network operations staff would ever be able to do it 
> correctly.  So as a community we decided not to go down that path.

In the late 1990s I was doing web server things at Demon Internet. Our “Homepages” service provided an IP-based virtual 
host for each customer (it predated widespread support for HTTP Host: headers), and by the time I joined the service 
had two /18s and a /16 of web sites (if my memory is correct). We were allocating addresses to customers sequentially, 
so the /18s were full and the /16 was in progress.

We had a small number of front-end Squid reverse proxy caches which owned all the IP addresses, using a BSD kernel hack 
(which I worked on to get published but it never got committed upstream 
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=12071)

The problem was that the entirely static load spreading relied on the routing config upstream from the reverse proxies, 
and IIRC it just divided the space into /18s and allocated them to proxies. So the load allocation was very uneven.

I thought up a cunning hack, to divide the /16 by using a non-contiguous netmask of 0xffff0003 instead of 0xffffc000, 
so that successive customers would be allocated to front ends 0,1,2,3 cyclically. Fun :-)

But I observed that one of my colleagues had a CIDR chart stuck on the side of his monitor, and that all the 
documentation in this area warned of dragons and bugs, and I realised that it would be unwise to do more than try it 
out experimentally :-)

Tony.
-- 
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