05-21-2009 06:08 AM - edited 03-06-2019 05:51 AM
hi,
We have 3550 L3 swicth and have configured three VLANs Viz : VLAN_A,VLAN_B,VLAN_C. With three different subnets as 10.1.1.0 /24, 10.2.1.0 /24 and 10.3.1.0 /24. Plus there is one routed interface connected to firewall inside switch ( subnet 192.168.1.10 /24) this is also a default route configured in L3 switch. What we need is that VLAN_B and VLAN_C shold not comminicate with each other. But should be able to communicate with default gateway. In short VLAN_B pc should not ping to VLAN_C and vice-a-versa.
Can it be implemented using VACL?
Private VLANs seems one option. But is there any option available? Can we just configure access-list like routers and apply it to vlan interface? So that it will act just like router interfaces so that any traffic originating from one VLAN and destined for another will hit this access-list and the corresponding action will be taken.
Please share any experience.
Any link on cisco.com?
Thanks in advance
Subodh
05-21-2009 07:00 AM
Any of your options should work. The L3 ACL probably has the most overhead so don't forget about that. Here's a link that might help.
http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a008013565f.shtml
05-22-2009 01:39 PM
Hi ,
Use "switch port protected" on all server ports to prevent them from talking to each other.
Another ugly way would be to use vlan maps to filter ARP.
mac access-list extended MACL
permit any
permit
mac access-list extended DROP
permit any any 0x806 0x0
vlan access-map block-arp 10
action forward
match mac address MACL
vlan access-map block-arp 20
action drop
match mac address ARP-DROP
vlan access-map block-arp 30
action forward
vlan filter block-arp vlan-list 10,20,30
Please note that methods mentioned above are locally significant, unlike pvlans.
-Rakesh
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