From: Curtis Phillips (phillipscurtis@xxxxxxxxxxxx)
Date: Tue Jun 12 2001 - 23:16:41 GMT-3
The network specified in the network mask is not 33 but 32.
255.255.255.224 = /27 = network 32 not 33.
Enter network 192.168.32.0 under the igrp and see if it works.
Curtis
Mike Gutknecht <mike@justcisco.com> wrote:
>
> I think of the "network" commands in the router config mode as enabling
> interfaces for routing. Those interfaces that fall within the network range
> specified are activated for routing. For IGRP, RIP, and EIGRP, the range is
> the implicit classful range.
>
> For a weird yet instructive example,
>
> int e0
> ip addr 10.1.1.1 255.255.255.0
> int e1
> ip addr 10.2.2.2 255.255.255.192
> int e2
> ip addr 10.3.3.3 255.255.255.224
>
> router igrp 1
> netw 10.0.0.0 -> Enables interfaces that represent networks within
> 10.0.0.0-10.255.255.255
>
> In this case, all three interfaces fall under the 10.0.0.0/8 network space
> so they are all enabled for IGRP. Now, IGRP will only send /24's out e0,
> /26's out e1 and /27's out e2. Also, because there is no mask information
> in recieved packets, it will assume that received routes on e0 are /24s,
> recieved routes on e1 are /26's, and received routes on e2 are /27's.
>
> Now, when you do what Carolyn did
>
> int e0
> ip addr 192.168.33.1 255.255.224.0
>
> router igrp 1
> netw 192.168.33.0
>
> the network associated with e0 is not entirely within the range specified by
> the network statement and thus is not activated. (I tested and got
> Carolyn's result as well.)
>
> Oddly, this behavior is different for OSPF where you are matching the
> interface's configured IP address rather than the network that the interface
> represents.
>
> -Mike G
>
>
>
>
>
> -----Original Message-----
> From: Rick Stephens [mailto:rstephens@wantec.com]
> Sent: Tuesday, June 12, 2001 10:32 AM
> To: 'GroupStudy'
> Cc: 'Carolyn Camarda'
> Subject: RE: IP Addressing & IGRP Question
>
>
> IGRP does not support VLSM, but it does support FLSM. All subnet masks must
> be of a fixed length. Since RIPv1 and IGRP routing updates do not include
> subnet mask information, a router will assume that the subnet mask with
> which it has configured on all its interfaces is the same for all subnets. A
> single mask must be used for all subnets of a given classful network.
> Different masks can be used for different classful network addresses.
> (Caslow p.300)
>
> I think Carolyn said that she tried with a /19 and it didn't work, but tried
> it again with a /30 and it did work. The question then would be is does IGRP
> support supernets (shorter then the classful boundry). Louie confirmed in
> his lab that a /19 can be used.
>
> Confirm 'ip classless'
>
> Maybe also look for a loopback address that is a different subnetmask? They
> all need to be the same.
>
>
> Just my $.02
>
>
>
> -----Original Message-----
> From: ElleJf(Yahoo) [mailto:ellejf@yahoo.com]
> Sent: Tuesday, June 12, 2001 9:43 AM
> To: louie kouncar
> Cc: 'GroupStudy'; 'Carolyn Camarda'
> Subject: RE: IP Addressing & IGRP Question
>
>
> I would be surprised if /19 mask can work. IGRP does not support VLSM, so
> that you can use 192.168.33.0/19 which is a classless subnet. This ip
> address belong to class C, so the mask should be /24. In IGRP routing
> update packets, only 192.168.33.0 will be recorded (In fact, 192.168.33, 3
> octets.) There is no info that you can know what the mask will be.
>
> The only way it would work is that router use locally configured subnet mask
> on interface, in this example, /19 as mask. But it doesn't make sense. Can
> you provide your config and network diagram?
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of louie
> kouncar
> Sent: Tuesday, June 12, 2001 1:18 PM
> To: 'Carolyn Camarda'; 'GroupStudy'
> Subject: RE: IP Addressing & IGRP Question
>
>
> Well,
>
> I just did a test to see if this is an issue, everything worked just
> fine using 192.168.33.1/19 on R1 and 192.168.33.2/19 on R2....
>
> Please post your full configs so I can look for issues....
>
>
> Thanks
>
> Louie Kouncar
> UUNET
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Carolyn Camarda
> Sent: Monday, June 11, 2001 11:21 PM
> To: GroupStudy
> Subject: IP Addressing & IGRP Question
>
> I'm having a mental block with some IGRP configuration, I would
> appreciate a
> little nudge. I have my router e0 interface set up with the IP address
> of
> 192.168.33.1/19. I have an IGRP network statement of 192.168.33.0.
> With
> this I do not get IGRP to start up on the E0 interface. I tried the
> network
> statement of 192.168.32.0 thinking that it may be wanting the VLSM
> network
> address. None the less I can not get IGRP to fire up.
>
> If I use a class a (10.) or class b (172.16.) address with the /19
> mask, I
> don't have a problem. When I change the 192 IP address on e0 to a
> longer
> mask, such as /30 it works fine. My code version is 12.0.5T. I have ip
> classless defined on the 2500 router
>
> Is there something with regards to IGRP when the mask can't be shorter
> than
> the classful boundary to which the address belongs. Or what am I doing
> wrong?
>
> Any help would be appreciated.
>
> Carolyn
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