From: Gregory W. Posey Jr. (gposey@xxxxxxxxxxx)
Date: Thu Apr 19 2001 - 10:53:32 GMT-3
If the question is why it does and address and wildcard mask (172.16.0.0
0.0.255.255), then 255.255.0.0 0.0.0.0 (or host) - that's because the second
part (255.255.0.0 0.0.0.0) says to explicitly use a 16 bit subnet mask ONLY
(255.255.0.0). Without that 2nd part, the access list would apply to
anything that has [172.16.] in the 1st two octets, regardless of the subnet
mask.
So the 1st address/wildcard pair is for the address and the 2nd
"address"/wildcard pair is for the subnet mask.
Thank you,
Greg Posey Jr.
CONECTS Network Analyst
CCNP - Security Specialist
Cisco Voice Access Specialist
www.conects.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Mohamed Heeba
Sent: Wednesday, April 18, 2001 1:35 PM
To: 'ccielab@groupstudy.com'
Subject: BGP access-list
guys ;
i noticed in Halabi 's book the following access list
access-list 101 permit ip 172.16.0.0 0.0.255.255 host 255.255.0.0
or
access-list 101 permit ip 172.16.0.0 0.0.255.255 255.255.0.0 0.0.0.0
in both cases the access-list will permit only 172.16.0.0 /16 ONLY .
any explansion for this access-list ,why it looks like that ???
thx
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