ipv6_addrs_IF aliases in rc.conf(5)

[Mark Felder]

On Wed, Jul 17, 2013, at 4:36, Hiroki Sato wrote:
> 
>  The recommended way is ifconfig_IF_aliasN or ifconfig_IF_aliases.
>  ipv4_addr_IF will not be removed in the near future, but please use
>  ifconfig_IF_alias{N,es} for newly-configured systems.  Backward
>  compatibility for not breaking the existing configurations will be
>  maintained as much as possible (even on the upcoming 10.0R and
>  later).
>

Almost everyone is familiar with ifconfig_IF_aliasN, but can you provide
example syntax for ifconfig_IF_aliases ? I've never seen that before and
can't find it documented.

> 
>  This is because we have a lot of variables which have (almost) the
>  same functionality in rc.conf and I want to simplify them by merging
>  them with each other, not because these are better than the others.
>  Variables with overlapped functionality have made difficult to
>  maintain/improve the rc.d scripts.
> 

I would actually prefer to see the ifconfig_IF_aliasN syntax go away
entirely as it simply cannot scale without becoming tedious. I know we
can't cover every edge case, but after discussing with people on this
list about the desire for ipv6_addrs_IF, now committed, it seems I'm not
the only example of this use case.

The best scenario I can describe is a situation where you have a shared
webhosting environment on FreeBSD. I may very well have 200 IPs on one
server. Being able to use ranges and CIDR syntax is invaluable. The idea
of ifconfig_IF_aliasN is not so bad as long as you never have to make
any changes. However, it's not uncommon to receive a work order from
sales where a customer needs to be moved from the shared webhosting
environment to their own private VM. We need to move the IP they were
using as we probably do not control DNS and it might be difficult for
the customer to get that changed. Removing an IP from the middle of 200
ifconfig_IF_aliasN entries requires you to renumber them all. This is
simply cruel and error-prone. Being able to adjust the ranges of
ipv4_addrs_IF is much cleaner and reliable.

This thread isn't exactly the proper forum to debate the future of
network configuration on FreeBSD, but please take this into
consideration. And thank you for your work on the rc.d scripts --
they're the #1 reason many of us prefer working with FreeBSD.