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Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
OL-8978-04
Chapter 15 Configuring Access Control
Using VACLs with Cisco IOS ACLs
Example 1
This example shows that the VACL does not follow the recommended guidelines (in line 9, a deny action
is defined instead of using the implicit deny action at the end of the ACL), and the resultant merge
increases the number of ACEs:
******** VACL ***********
1 permit udp host 194.72.72.33 194.72.6.160 0.0.0.15
2 permit udp host 147.150.213.94 194.72.6.64 0.0.0.15 eq bootps
3 permit udp 194.73.74.0 0.0.0.255 host 194.72.6.205 eq syslog
4 permit udp host 167.221.23.1 host 194.72.6.198 eq tacacs
5 permit udp 194.72.136.1 0.0.3.128 194.72.6.64 0.0.0.15 eq tftp
6 permit udp host 193.6.65.17 host 194.72.6.205 gt 1023
7 permit tcp any host 194.72.6.52
8 permit tcp any host 194.72.6.52 eq 113
9 deny tcp any host 194.72.6.51 eq ftp
10 permit tcp any host 194.72.6.51 eq ftp-data
11 permit tcp any host 194.72.6.51
12 permit tcp any eq domain host 194.72.6.51
13 permit tcp any host 194.72.6.51 gt 1023
14 permit ip any host 1.1.1.1
******** Cisco IOS ACL ************
1 deny ip any host 239.255.255.255
2 permit ip any any
******** MERGE **********
has 91 entries entries
Example 2
In
Example 1
, if you follow the guidelines and remove line 9 (the implicit deny is then used at the end
of the ACL) and modify lines 11 and 12 (lines 11 and 12 are modified so that the traffic that line 9 would
have dropped is not permitted), you see the following equivalent ACL with improved merge results:
********
VACL
**********
1 permit udp host 194.72.72.33 194.72.6.160 0.0.0.15
2 permit udp host 147.150.213.94 194.72.6.64 0.0.0.15 eq bootps
3 permit udp 194.73.74.0 0.0.0.255 host 194.72.6.205 eq syslog
4 permit udp host 167.221.23.1 host 194.72.6.198 eq tacacs
5 permit udp 194.72.136.1 0.0.3.128 194.72.6.64 0.0.0.15 eq tftp
6 permit udp host 193.6.65.17 host 194.72.6.205 gt 1023
7 permit tcp any host 194.72.6.52
8 permit tcp any host 194.72.6.52 eq 113
9 permit tcp any host 194.72.6.51 eq ftp-data
10 permit tcp any host 194.72.6.51 neq ftp
11 permit tcp any eq domain host 194.72.6.51 neq ftp
12 permit tcp any host 194.72.6.51 gt 1023
13 permit ip any host 1.1.1.1
******** Cisco IOS ACL ************
1 deny ip any host 239.255.255.255
2 permit ip any any
******** MERGE ***********
has 78 entries
Example 3
This example shows that the VACL does not follow the recommended guidelines (all the action types are
not grouped), and the resultant merge significantly increases the number of ACEs:
******** VACL ***********
1 deny ip 0.0.0.0 255.255.255.0 any
2 deny ip 0.0.0.255 255.255.255.0 any
3 deny ip any 0.0.0.0 255.255.255.0
4 permit ip any host 239.255.255.255
5 permit ip any host 255.255.255.255