OSPF, EIGRP...wildcards questions

binaryhat

Hello,

I'll try to be as clear as possible:

In Lammle's book, he only uses wildcards when configuring OSPF. In this lab packet--->https://learningnetwork.cisco.com/docs/DOC-12808, lab NA-4-4-EIGRP uses wildcards. So I'm confused...EIGRP uses wildcards when setting it up? Lammle does not mention wildcards in regards to EIGRP.

His book says:

Router(config)#router eigrp 20
Router(config-router)#network 172.16.0.0
Router(config-router)#network 10.0.0.0

as an example.


My other question is with OSPF:

In lab NA-4-3-OSPF I'm having trouble understanding where these two network statements come from:

Ranet-BR(config-router)#network 128.0.6.156 0.0.0.3 area 0
Ranet-HQ(config-router)#network 128.0.6.156 0.0.0.3 area 0


I see where these two come from (both are the subnets of the two LAN's):

Ranet-BR(config-router)#network 128.0.6.144 0.0.0.7 area 0
Ranet-HQ(config-router)#network 128.0.6.128 0.0.0.15 area 0

sizeon

1) With EIGRP, wildcards are OPTIONAL. You do not have to use them.

2) Not really sure what you are asking but 0.0.0.3 is the same as 0.0.0.252

Roguetadhg

I suspect you mean to say: 255.255.255.252. This isn't the same as 0.0.0.3. First is a subnet mask. Not a wild-card mask. Reverse, yes. Not the same. Not used interchangeably. Mostly... I say mostly because of what I'm about to show you!

255.255.255.252 = 1111 1111.1111 1111.1111 1111.1111 1100
0.0.0.3 = 0000 0000 . 0000 0000 . 0000 0000.0000 0011

However... For EIGRP, you can input either wild-card or a subnet mask. It will show the wild-card on a show run. Just know it can take Wild-card, like OSPF. It can also not use any mask and rely on the class boundaries! Amazing!

Heres some input I pulled up to show you the latter information

Gunther(config)#router eigrp 1
Gunther(config-router)#[COLOR=#ff0000]network 10.0.0.0[/COLOR][COLOR=#0000ff] [B] 255[/B][/COLOR][COLOR=#ff0000][B].[/B][/COLOR][COLOR=#0000ff][B]255[/B][/COLOR][COLOR=#ff0000][B].[/B][/COLOR][COLOR=#0000ff][B]255[/B][/COLOR][COLOR=#ff0000][B].[/B][/COLOR][COLOR=#008000][B]0[/B][/COLOR]
Gunther(config-router)#network 12.0.0.0
Gunther(config-router)#network 14.0.0.0 0.0.0.255
Gunther(config-router)#do show run | se router
router eigrp 1
 [COLOR=#ff0000]network 10.0.0.0[/COLOR] [COLOR=#008000][B] 0[/B][/COLOR][COLOR=#ff0000][B].[/B][/COLOR][COLOR=#008000][B]0[/B][/COLOR][COLOR=#ff0000][B].[/B][/COLOR][COLOR=#008000][B]0[/B][/COLOR][COLOR=#ff0000][B].[/B][/COLOR][COLOR=#0000ff][B]255[/B][/COLOR]
 network 12.0.0.0
 network 14.0.0.0 0.0.0.255
 auto-summary
Gunther(config-router)#

Can't open the topologies - I guess I don't have packet tracer installed. I can't find the installation file on my computer

vishaw1986

Hey

If you want to run EIGRP on a specific interface , then use network command with the wild card mask .
E.g Suppose you hav ethree interface with address 1.1.1.1 , 1.1.2.1 , 1.1.3.1 with /24 mask each. You colud just use classfull network command with 1.0.0.0 and this would enable eigrp on all interface that start with 1 . And If you don't want your network to learn 1.1.2.1 address through eigrp , in that case your use wildcard mask . Network 1.1.1.0 0.0.0.255 and 1.1.3.0 0.0.0.255 . In this manner EIGRP get enable on all interface except 1.1.2.1 . Hope this helps you

For Your Next question , m not able to open the topology in my system , so sorry .

sizeon

Roguetadhg wrote: »

I suspect you mean to say: 255.255.255.252. This isn't the same as 0.0.0.3. First is a subnet mask. Not a wild-card mask. Reverse, yes. Not the same. Not used interchangeably. Mostly... I say mostly because of what I'm about to show you!

255.255.255.252 = 1111 1111.1111 1111.1111 1111.1111 1100
0.0.0.3 = 0000 0000 . 0000 0000 . 0000 0000.0000 0011

However... For EIGRP, you can input either wild-card or a subnet mask. It will show the wild-card on a show run. Just know it can take Wild-card, like OSPF. It can also not use any mask and rely on the class boundaries! Amazing!

Heres some input I pulled up to show you the latter information

Gunther(config)#router eigrp 1
Gunther(config-router)#[COLOR=#ff0000]network 10.0.0.0[/COLOR][COLOR=#0000ff] [B] 255[/B][/COLOR][COLOR=#ff0000][B].[/B][/COLOR][COLOR=#0000ff][B]255[/B][/COLOR][COLOR=#ff0000][B].[/B][/COLOR][COLOR=#0000ff][B]255[/B][/COLOR][COLOR=#ff0000][B].[/B][/COLOR][COLOR=#008000][B]0[/B][/COLOR]
Gunther(config-router)#network 12.0.0.0
Gunther(config-router)#network 14.0.0.0 0.0.0.255
Gunther(config-router)#do show run | se router
router eigrp 1
 [COLOR=#ff0000]network 10.0.0.0[/COLOR] [COLOR=#008000][B] 0[/B][/COLOR][COLOR=#ff0000][B].[/B][/COLOR][COLOR=#008000][B]0[/B][/COLOR][COLOR=#ff0000][B].[/B][/COLOR][COLOR=#008000][B]0[/B][/COLOR][COLOR=#ff0000][B].[/B][/COLOR][COLOR=#0000ff][B]255[/B][/COLOR]
 network 12.0.0.0
 network 14.0.0.0 0.0.0.255
 auto-summary
Gunther(config-router)#

Can't open the topologies - I guess I don't have packet tracer installed. I can't find the installation file on my computer

0.0.0.252 is the same thing as 0.0.0.3.

binaryhat

Definitely helps...wildcards are optional for EIGRP...except useful in this case:

If you want to run EIGRP on a specific interface , then use network command with the wild card mask .
E.g Suppose you hav ethree interface with address 1.1.1.1 , 1.1.2.1 , 1.1.3.1 with /24 mask each. You colud just use classfull network command with 1.0.0.0 and this would enable eigrp on all interface that start with 1 . And If you don't want your network to learn 1.1.2.1 address through eigrp , in that case your use wildcard mask . Network 1.1.1.0 0.0.0.255 and 1.1.3.0 0.0.0.255 . In this manner EIGRP get enable on all interface except 1.1.2.1 . Hope this helps you

Wildcards are required for OSPF.

If any of can help me clear up my PT Lab questions that would be great.

luberguilarte

You wrong , 0.0.0.252 is nothing in the cisco world , you mean 255.255.255.252 if you want to apply that subnet mask to wild-card it will be 0.0.0.3.

sizeon

Thats what i meant. 255.255.255.252 is the same as 0.0.0.3

Roguetadhg