From: Rodgers Moore (rodgers@xxxxxxxxxxxxxx)
Date: Thu May 31 2001 - 22:44:04 GMT-3
Two weeks? I'll be there the 11th & 12th.
The bug I ran into in 12.0.5 was the wild card had to match the inverse mask of
the interface exactly. So, we're stuck
with the same answer, "it depends...". :)
Rodgers Moore
Matthew.Sypherd@rrd.com wrote:
> Just thought of something...
>
> If you are concerned that this bug may cause problems in the lab, would
> using a wildcard mask of 0.0.0.1 solve this dilemma? (Assuming there are no
> other potential interface addresses within that very small range)
> This way, we can continue to specify interfaces finely, and possibly avoid
> the potential problems of this bug.
>
> I don't have access to my lab right now, so can someone try this out in a
> situation where the 0.0.0.0 was not redistributed, or can someone point out
> potential problems with this method?
> I've been using 0.0.0.0 masks for everything (unless specified otherwise in
> the practice lab) and I would like to avoid problems without having to
> totally rethink this on the fly. (Yeah, yeah, I know, but... tick
> tock...tick tock)
>
> To note, I always do a "o int" (alias exec o show ip ospf ) to verify I
> have the correct interfaces defined in my OSPF process. I've caught
> multiple omissions and typos with this!
>
> RTP in 2 weeks and counting....My goodness how time flies!!!
>
> Matthew C. Sypherd
> CCNP+Security CCDP MCSE CCSE
>
>
> Jim Graves
> <jtg@lucent.c To: Brian Hescock <bhescock@cisc
o.com>, "Jeff K." <jeffbk@austin.rr.com>
> om> cc: Mike Hess <mahess@home.com>,
<ccielab@groupstudy.com>
> Sent by: Subject: Re: 0.0.0.0 wildcard bi
ts and redistribution
> nobody@groups
> tudy.com
>
>
> 05/29/2001
> 08:22 AM
> Please
> respond to
> Jim Graves
>
>
>
> I can't think of any reason a 0.0.0.0 wildcard mask should make a
> difference either -- but it does. Give it a try. Last night, I set up the
> situation Walter talks about, and to my shock and horror he was right. I
> used a 0.0.0.0 wildcard mask, and the network didn't show up. When I
> changed the network statement to use a 0.0.0.255 wildcard mask, the network
> showed up in EIGRP. Huh.
>
> The same thing happens in bootcamp lab 3 if you replace the EIGRP LAN
> network with some other network outside 137.20.0.0/16. I tried it with
> both 192.168.50.0/24 and 172.20.50.0/24 (to rule out any kind of classful
> silliness). Again, when I used 0.0.0.0, the connected network didn't show
> up. With 0.0.0.255, it did. The same thing happened when I tried RIP v2
> or a second OSPF process instead of EIGRP.
>
> Why? Beats the heck out of me. I tested this using IOS versions 12.0(11),
> 12.0(15), and 12.0(7)T. I don't know if it's a bug of a feature, but it
> sure is weird.
>
> Jim
>
> At 10:35 PM 5/28/2001 -0400, Brian Hescock wrote:
> >I can't think of any way using a 0.0.0.0 wildcard bits would affect
> >redistribution, unless it's a bug. All the ospf network command does is
> >turn on ospf on
> >the interface(s) covered by the network statement, that's all it does. It
> >has zero effect on the network mask being advertised and no effect on
> >redistribution. To everyone that said use a 0.0.0.0 mask (wildcard bits
> >actually), thumbs up, it's the preferred method unless you have a lot of
> >interfaces you need to turn
> >ospf on. Not just for lab use but for production networks as well. Less
> >chance for error and easier to troubleshoot.
> >
> >Brian
> >
> >On Mon, 28 May 2001, Jeff K. wrote:
> >
> > > You are exactly right with all the shortcuts. I've never considered
> using
> > > aliases because I never use them day to day and know that it will wind
> up
> > > slowing me down since I type pretty fast. I know that I can calculate
> a
> > > wildcard mask easily and don't have a problem with it. Not my point,
> > > though... I was merely asking for an explanation as to why using the
> > > 0.0.0.0 area mask would affect route redistribution, which is a
> question
> > > that hasn't been answered. In my opinion, it makes good common sense
> > as you
> > > put it to use the 0.0.0.0 mask except when using a wildcard mask that
> will
> > > allow you to group multiple interfaces into a single area (i.e., a
> single
> > > statement versus multiple statements). Since I always use logic when
> > > assigning my interface addressing schemes, the all 0 mask allows me to
> > > double check everything quickly and easily - I know what interface has
> what
> > > address and where it should be. Not that the wildcard mask makes that
> any
> > > more difficult - just my personal preference. If a bug or other
> > > 'undocumented feature' requires me to use the exact mask, I will be
> fine as
> > > well... Anyway, if you have an answer for my original question about
> why
> > > the area mask affects route redistribution (what I originally responded
> > to),
> > > please respond. I am more curious than anything.
> > >
> > > Thanks,
> > >
> > > -Jeff
> > > ----- Original Message -----
> > > From: "Mike Hess" <mahess@home.com>
> > > To: <ccielab@groupstudy.com>
> > > Sent: Monday, May 28, 2001 7:06 PM
> > > Subject: RE: how anal is the lab grading
> > >
> > >
> > > > Why not just be smart and use a network statement and the right
> wildcard
> > > > mask for every interface that you are putting into OSPF? It seems
> common
> > > > sense to me not to try and get too pretty or cut too many corners and
> > then
> > > > get end up with a problem with 15 minutes left just because you were
> too
> > > > lazy to be more specific in the first place.
> > > >
> > > > Some people advocate the use of too many shortcuts. I see a lot of
> people
> > > > advocating shortcuts such as this, using a whold slew of alias
> commands,
> > > > etc. Just learn the material and don't try to save seconds when it's
> the
> > > > minutes and hours that really matter.
> > > >
> > > > Back to my original point, if you cannot at this point calculate a
> simple
> > > > wildcard mask then you are going for the wrong certification. Perhaps
> it
> > > is
> > > > not the grading.... :-)
> > > >
> > > > -----Original Message-----
> > > > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf
> Of
> > > > Jeff K.
> > > > Sent: Monday, May 28, 2001 5:27 PM
> > > > To: Walter Chen; Peter Van Oene; ccielab@groupstudy.com
> > > > Subject: Re: how anal is the lab grading
> > > >
> > > >
> > > > You lost me on the second paragraph. Why would using the 0.0.0.0
> > > wild-card
> > > > mask for interface area identification affect redistribution? This
> mask
> > > > just allows you to use the interface's address. Obviously the subnet
> > mask
> > > > of your interfaces will affect redistribution, but I don't see how
> the
> > > > 0.0.0.0 area mask will. You can definitely mess up your OSPF
> topology by
> > > > using the wrong mask (i.e., interfaces in the wrong area, interfaces
> > added
> > > > to OSPF that weren't supposed to be). Let me know what your thoughts
> are
> > > on
> > > > this. Maybe I am forgetting something or am just misunderstanding
> > > > something.
> > > >
> > > > Thanks,
> > > >
> > > > -Jeff
> > > > ----- Original Message -----
> > > > From: "Walter Chen" <wchen@iloka.com>
> > > > To: "Peter Van Oene" <pvo@usermail.com>; <ccielab@groupstudy.com>
> > > > Sent: Monday, May 28, 2001 3:04 PM
> > > > Subject: Re: how anal is the lab grading
> > > >
> > > >
> > > > > IMHO, you can use 0.0.0.255 mask if you have other 1.1.1.x/29
> networks
> > > > onthe
> > > > > same router and they also belong to the same OSPF area. However,
> if
> > > these
> > > > > networks should not be in OSPF or in the same area, you definitely
> > > should
> > > > > not use 0.0.0.255 mask. The absolutely sure and correct way is to
> use
> > > > > 0.0.0.7 mask for 1.1.1.0/29 network.
> > > > >
> > > > > You can use 0.0.0.0 mask in cases if you do not need to
> redistribute
> > > > > 1.1.1.0/29 into other routing protocols on this same router.
> However,
> > > if,
> > > > > say, your 192.168.1.0/24 belongs to EIGRP and you want to
> reistribute
> > > > > between OSPF and EIGRP, the 1.1.1.0/29 network will NOT be passed
> into
> > > > EIGRP
> > > > > if you have used 0.0.0.0 mask.
> > > > >
> > > > > Walter
> > > > >
> > > > > ----- Original Message -----
> > > > > From: Peter Van Oene <pvo@usermail.com>
> > > > > To: <ccielab@groupstudy.com>
> > > > > Sent: Monday, May 28, 2001 9:35 AM
> > > > > Subject: Re: how anal is the lab grading
> > > > >
> > > > >
> > > > > > Personally, I'd not use 0.0.0.255 in any case, lab or otherwise.
> The
> > > > full
> > > > > 0's mask is the safe and accurate way to add interfaces to the OSPF
> > > > process
> > > > > and unless you need to add 20 odd interfaces, I'd suggest you use
> it.
> > > As
> > > > > far as the lab goes, I can attest that lab grading is fair. You
> > > shouldn't
> > > > > worry about trivial semantics. If your prepared, you'll likely
> have a
> > > > good
> > > > > idea when you are using an illegal shortcut.
> > > > > >
> > > > > > Pete
> > > > > >
> > > > > >
> > > > > > *********** REPLY SEPARATOR ***********
> > > > > >
> > > > > > On 5/28/2001 at 7:48 AM Don Dettmore wrote:
> > > > > >
> > > > > > >Question - How nit-picky are the graders of the lab? F0r
> example,
> > > > > > >something
> > > > > > >occurred to me when I was working in the lab:
> > > > > > >
> > > > > > >192.168.1.0 /24 ------ R1 ----- 1.1.1.0 /29
> > > > > > >
> > > > > > >When configuring R1 for OSPF, would the following be acceptable:
> > > > > > >
> > > > > > >network 1.1.1.0 0.0.0.255 area 0.0.0.0
> > > > > > >
> > > > > > >Or would that be considered wrong because of the 'wrong' (or I
> > should
> > > > > say -
> > > > > > >not specific enough) wildcard mask.
> > > > > > >
> > > > > > >Just wondering how anal I must train myself to be.
> > > > > > >
> > > > > > >Don Dettmore
> > > > > > >**Please read:http://www.groupstudy.com/list/posting.html
> > > > > > **Please read:http://www.groupstudy.com/list/posting.html
> > > > > **Please read:http://www.groupstudy.com/list/posting.html
> > > > **Please read:http://www.groupstudy.com/list/posting.html
> > > > **Please read:http://www.groupstudy.com/list/posting.html
> > > **Please read:http://www.groupstudy.com/list/posting.html
> >**Please read:http://www.groupstudy.com/list/posting.html
> **Please read:http://www.groupstudy.com/list/posting.html
> **Please read:http://www.groupstudy.com/list/posting.html
**Please read:http://www.groupstudy.com/list/posting.html
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