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Wild Card Mask

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Last Modified: 2017-11-16
Network
In the topology above , I have EIGRP configured on both routers.
I have advertised all the networks to EIGRP

these are the interfaces in R2:
R2(config-router)# do show ip interface bri
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet0/0            192.168.12.2    YES manual up                    up      
FastEthernet0/1            unassigned      YES unset  administratively down down    
FastEthernet1/0            unassigned      YES unset  administratively down down    
FastEthernet1/1            unassigned      YES unset  administratively down down    
Loopback0                  172.16.0.2      YES manual up                    up      
Loopback1                  172.16.1.2      YES manual up                    up      
Loopback2                  172.16.2.2      YES manual up                    up      
Loopback3                  172.16.3.2      YES manual up                    up      
R2(config-router)#

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in R2 , when I advertise R2(config-router)#network 172.16.0.0 0.0.3.255
I do not get any error, and all 172.x.x.x networks will show up in R1 routing table:

R1#sh ip route  eigrp 

Gateway of last resort is not set

      172.16.0.0/24 is subnetted, 4 subnets
D        172.16.0.0 [90/156160] via 192.168.12.2, 00:02:02, FastEthernet0/0
D        172.16.1.0 [90/156160] via 192.168.12.2, 00:02:02, FastEthernet0/0
D        172.16.2.0 [90/156160] via 192.168.12.2, 00:02:02, FastEthernet0/0
D        172.16.3.0 [90/156160] via 192.168.12.2, 00:02:02, FastEthernet0/0
R1#

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but if I try different wild card mask I get error  :
R2(config-router)#network 172.16.0.0 0.0.4.255
%EIGRP: Invalid mask (discontiguous)

but if I try these wild card masks one a time after Negating one of them , it will work:
R2(config-router)#network 172.16.0.0 0.0.1.255
R2(config-router)#network 172.16.0.0 0.0.0.255  

***So the ones that worked (one a time) are:
R2(config-router)#network 172.16.0.0 0.0.1.255
R2(config-router)#network 172.16.0.0 0.0.0.255  
R2(config-router)#network 172.16.0.0 0.0.3.255

the :172.16.0.0 0.0.2.255 ,172.16.0.0 0.0.4.255,172.16.0.0 0.0.5.255........172.16.0.0 0.0.254.255

I get this error :%EIGRP: Invalid mask (discontiguous)

Any idea why  ?

Thank you
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