This argument has come up several times and In most cases it is a matter
of preference. It does actually make a difference in how these routes
are treated. For 90% or more of the people it will not make a difference
and you choose your preference. Some like to use the networks statement
as an ACL of sorts, but that is not its intended role. Truly how OSPF
was desinged the networks are the actual interfaces that belong on the
OSPF routing network that is why they are announced by default if they
are included. On most networks especial if your using a software based
routing like Mikrotik or hardware ASIC based systems like Brocade. If
you are using Mikrotik and only have an area 0 then you will never see
any issues either way. You are probably not worried about sub 50ms
rerouting and other such features that this can change how routing
behaves. If you redistribute networks those specific addresses belong in
a different place for OSPF than when it is added to the networks. When
added to the networks it becomes part of the link state database as
well. which won't make any difference unless it is either a very large
amount of routes or you have a very large network. Routes that are
redistributed are not part of the link state database. They are also
treated differently when it comes to routing decisions. This can have a
negative repercussions if you are distributing a great deal of routes
especially if using some hardware based routing platforms. On the other
hand if you want the addresses to be quicker if that interface goes down
then you would want to add it to the networks. I am talking about very
insignificant differences and very on routing platforms to the point
that it really won't matter for most people.
Me personally I prefer to redistribute both static and connected routes
and use very strict route filtering because it allows for much more
control. For example I filter out all the /32 networks that get assigned
for PPP and actually only allow the pool assigned to that router and a
range for the statics so that all other addresses won't be
redistributed. This also carries over easily to BGP. On the other hand
I set up ospf using networks for a great deal of my clients because it
is easier to maintain and understand what is being routed.
On 05/21/2015 05:34 PM, Dennis Burgess wrote:
Oh I agree, if it works for you fine. Just giving you the example of
why as you grow your knowledge and experience, you typically do it
this way. Jno worries!
Dennis Burgess, CTO, Link Technologies, Inc.
den...@linktechs.net <mailto:den...@linktechs.net> – 314-735-0270 –
www.linktechs.net <http://www.linktechs.net>
*From:*Af [mailto:af-boun...@afmug.com] *On Behalf Of *Ken Hohhof
*Sent:* Thursday, May 21, 2015 2:07 PM
*To:* af@afmug.com
*Subject:* Re: [AFMUG] mt ospf question
That’s right. I’d better request an advisory ruling.
*From:*George Skorup <mailto:geo...@cbcast.com>
*Sent:*Thursday, May 21, 2015 12:45 PM
*To:*af@afmug.com <mailto:af@afmug.com>
*Subject:*Re: [AFMUG] mt ospf question
Easily negated with a routing filter on the OSPF-out chain. We can all
argue this all day long. Nobody is wrong. Run your network how you
want.. until the FCC starts dictating routing config too. :|
On 5/21/2015 12:39 PM, Dennis Burgess wrote:
You have tech ports on your routers, say, 10.199.199.1/24 on each
site. That is a private block that you NAT at each site just for
your on-site tech to use if needed.. now, the issue, all of your
routers are advertising and basically arguing who has
10.199.199.0/24 !
