Either method will work fine, it is MOSTLY a matter of preference. When I say mostly I mean that if you are not going to use the very specific 0.0.0.0 inverse mask, make very sure you know EXACTLY what interfaces you are actually advertising with a more broad inverse mask.
When we get to the CCIE level, my preferred method is to exactly match every interface with a 0.0.0.0 wildcard mask. The reason is that it is much more specific and you don't end up unintentionally advertising things you don't want into a routing protocol. In the real world, your general 0.0.0.255 mask is probably OK. In the CCIE lab, lock everything down as tight as you can here and you will likely avoid a headache later on. So to summarize here, functionally they both add interfaces, but I would recommend locking it down tighter with the 0.0.0.0 mask On Mon, Aug 31, 2009 at 10:52 PM, Rick Mur <[email protected]> wrote: > Indeed some people make it a habit of specifying the inverse mask of the > subnet-mask of the interface they want to enable OSPF on. As Bryan said, > there is absolutely no reason for doing that, unless a task only allows you > to use one or a specific number of network statements. > Both in the CCIE lab and in real life you want to be as specific as > possible, so by using a 0.0.0.0 inverse mask you only match on the given IP > address and you will never run into strange things. Saves another > frustration during your exam :-) > > -- > > Regards, > > Rick Mur > CCIE2 #21946 (R&S / Service Provider) > Sr. Support Engineer – IPexpert, Inc. > URL: http://www.IPexpert.com > > > On Tue, Sep 1, 2009 at 4:33 AM, Bryan Bartik <[email protected]> wrote: > >> Hello Uli, >> >> The only reason I can think of not to use 0.0.0.0 is when you want to >> cover more the one interface with the network statement. It certainly does >> not need to match the subnet mask and there is no functional difference if >> it does or not. >> >> -hth >> >> >> On Mon, Aug 31, 2009 at 7:13 PM, Stan <[email protected]> wrote: >> >>> They are both valid and it all depends on how specific you need to be >>> in enabling OSPF. Ipexpert workbooks will walk you trough, just keep >>> reading..:) >>> >>> Stan >>> >>> >>> >>> On 8/31/09 6:10 PM, "Uli" <[email protected]> wrote: >>> >>> Hi guys, >>> >>> When I studied CCNP in CNAP we configure ospf wildcard masks just using >>> the reverse of netmask. However, in CCIE we need to be more specific so we >>> use 0.0.0.0 for wildcard masks. Does anyone know what the difference between >>> them and which one is more prefer in exam lab ? >>> >>> Cheers :) >>> >>> ------------------------------ >>> _______________________________________________ >>> For more information regarding industry leading CCIE Lab training, please >>> visit www.ipexpert.com >>> >>> >>> _______________________________________________ >>> For more information regarding industry leading CCIE Lab training, please >>> visit www.ipexpert.com >>> >>> >> >> >> -- >> Bryan Bartik >> CCIE #23707 (R&S), CCNP >> Sr. Support Engineer - IPexpert, Inc. >> URL: http://www.IPexpert.com >> >> _______________________________________________ >> For more information regarding industry leading CCIE Lab training, please >> visit www.ipexpert.com >> >> > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > -- Regards, Joe Astorino - CCIE #24347 R&S Technical Instructor - IPexpert, Inc. Cell: +1.586.212.6107 Fax: +1.810.454.0130 Mailto: [email protected]
_______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
