Brocade Communications Systems Layer 3 Routing Configuration ICX 6650 - Manual (Page 217)

Brocade ICX 6650 Layer 3 Routing Configuration Guide 199
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Configuring OSPF
The first three commands configure an extended ACL that denies routes to any 10.x.x.x destination
network with a 255.255.0.0 network mask and allows all other routes for eligibility to be installed
in the IP route table. The last three commands change the CLI to the OSPF configuration level and
configure an OSPF distribution list that uses the ACL as input. The distribution list prevents routes
to any 10.x.x.x destination network with network mask 255.255.0.0 from entering the IP route
table. The distribution list does not prevent the routes from entering the OSPF database.
Syntax: [no] ip access-list extended ACL-name | ACL-id
Syntax: deny | permit ip-protocol source-ip wildcard destination-ip wildcard
The ACL-name | ACL-id parameter specifies the ACL name or ID.
The deny | permit parameter indicates whether packets that match the policy are dropped or
forwarded.
The ip-protocol parameter indicates the type of IP packet you are filtering. When using an extended
ACL as input for an OSPF distribution list, specify ip.
Because this ACL is input to an OSPF distribution list, the source-ip parameter actually specifies the
destination network of the route.
The wildcard parameter specifies the portion of the source address to match against. The wildcard
is in dotted-decimal notation (IP address format). It is a four-part value, where each part is 8 bits
(one byte) separated by dots, and each bit is a one or a zero. Each part is a number ranging from 0
to 255, for example 0.0.0.255. Zeros in the mask mean the packet source address must match
the source-ip. Ones mean any value matches. For example, the source-ip and wildcard values
10.0.0.0 0.255.255.255 mean that all 10.x.x.x networks match the ACL.
If you want the policy to match on all network addresses, enter any any.
If you prefer to specify the wildcard (mask value) in Classless Interdomain Routing (CIDR) format,
you can enter a forward slash after the IP address, then enter the number of significant bits in the
mask. For example, you can enter the CIDR equivalent of “10.0.0.0 0.255.255.255” as
“10.0.0.0/8”. The CLI automatically converts the CIDR number into the appropriate ACL mask
(where zeros instead of ones are the significant bits) and changes the non-significant portion of the
IP address into zeros.
Brocade(config)#ip access-list extended no_ip
Brocade(config-ext-nACL)#deny ip 10.0.0.0 0.255.255.255 255.255.0.0 0.0.255.255
Brocade(config-ext-nACL)#permit ip any any
Brocade(config-ext-nACL)#exit
Brocade(config)#router ospf
Brocade(config-ospf-router)#distribute-list no_ip in