From: LASSERRE Grégory (gregory.lasserre@xxxxxxxx)
Date: Fri Apr 21 2000 - 09:55:17 GMT-3
Sorry for the mistakes...
In english this time :o)
> Just a tip if you do not want to make any mistake configuring
> your wildcards :
>
> DO NOT CONFIGURE IT !
>
> Use a standard IP mask, OSPF will translate it for you in wildcards....
> (i definitely use it in 12.0, but i think this should work since 11.2)
>
> My 2 cents...
>
> Greg.
>
> -----Message d'origine-----
> De: Chad Marsh [SMTP:chad@wa.net]
> Date: vendredi 21 avril 2000 05:12
> À: CCIELAB
> Objet: Re: OSPF reverse mask
>
> I agree with the majority, easier to use a 0.0.0.0 mask specifying
> each
> interface that is participating in OSPF, unless all router
> interfaces are
> participating, then one statement of :
> network 0.0.0.0 255.255.255.255 area x
> is more sensible
>
> However, you should be just as comfortable calculating inverse masks
> as you
> are standard ones, basically there are only 8 variations of each:
>
> Standard Inverse
> 255 0
> 254 1
> 252 3
> 248 7
> 240 15
> 224 31
> 192 63
> 128 127
> 0 255
>
> so 255.255.224.0 standard is 0.0.31.255 inverse
> or 255.255.255.240 standard is 0.0.0.15 inverse
>
> etc.
>
> In my experience, you are more likely to blow an inverse mask in an
> access-list than in an OSPF network statement, cause you'll do way
> more of
> them...
>
>
> Chad Marsh
> CCIE# 5185
>
> ----- Original Message -----
> From: Stanley Seow <stanley_seow@techno-craft.com.sg>
> To: CCIELAB <ccielab@groupstudy.com>
> Sent: Thursday, April 20, 2000 6:42 AM
> Subject: OSPF reverse mask
>
>
> > A quick question....
> >
> > For example, if the OSPF area X have a /22 bit mask...for the
> configuration
> > on the router, can I use the specific interface IP address (host
> mask )
> >
> > network 172.16.1.1 0.0.0.0 area 0
> > network 172.16.5.1 0.0.0.0 area 1
> >
> > instead of calculating the reverse mask for odd subnet bit like
> /22 /25
> /26
> > /27.
> >
> > What is the differences betwen the above two reverse mask ??
> >
> > Stanley
> >
> >
> >
> >
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