05-21-2006 07:01 AM - edited 03-03-2019 12:46 PM
Hi all,
I am using a 3550 for layer 3 routing to allow all VLANs to use a common firewall. Basically VLANs are 10.1.0.0/16, 10.2.0.0/16 and so on and port 172.16.0.0/16 which is in the firewalls subnet. I want all VLANs to be able to access the firewall but no allow the client VLANs to access each other. Do I need to do this with ACLs? I would like the setup as simple as possible.
05-21-2006 08:16 AM
Yes, you will need an ACL that will prevent vlan 10.1 from talking to vlan 10.2 and vise versa. It's a simple Access-list, for example:
access-list 1 deny 10.2.0.0 0.0.255.255
access-list 2 deny 10.1.0.0 0.0.255.255
interface vlan 1
ip access-group 2 out >> will prevent any traffic from 10.2.0.0
interface vlan 2
ip access-group 1 out >> will prevent any traffic fomr 10.1.0.0
Please rate helpful post.
05-21-2006 08:23 AM
hi would this work also?
access-list 101 permit ip any any
access-list 101 deny ip 10.0.0.0 0.255.255.255 10.0.0.0 0.255.255.255
interface vlan x
access-group 101 out
ie stop and 10.0.0.0 accessing any other?
05-21-2006 10:47 AM
I do not see any reason why it would not work but have the deny first before the permit.
Please rate helpful posts.
05-22-2006 02:33 AM
access-list 101 deny ip 10.0.0.0 0.255.255.255 10.0.0.0 0.255.255.255
access-list 101 permit ip any any
vlan x
ip access-group 1010 out
This prevents a host in 10.14.0.0/16 pinging a host in 10.15.0.0/16.
However I am still able to ping 10.15.0.1 (vlan15 IP) from 10.14.0.0/16
10.15.0.1 is the IP assigned to the VLAN associated with the interface. These address act as the default gw for the clients. No sure how this is possible.
05-22-2006 02:58 AM
HI
From where u r trying to ping this IP.r u pigning it from any hosts or from the router itself.
Thanks
mahmood
05-22-2006 04:57 AM
Hi if I ping from the host I am able to ping the other VLAN GW IPs but not any host in those networks.
05-22-2006 05:23 AM
Hi
Can u check applying this access-list inbound and verify wearther u r able to ping the G/W address.
Thanks
Mahmood
05-22-2006 05:39 AM
Hi if I apply in "in" as well as "out" I cannot the ping any VLAN GW.
I can access internet etc ok though via this port.
This is probably ok but it would be nice to ping the local GW from its respective VLAN.
06-04-2006 05:13 AM
Do you guys think this is feasible solution when a person have more than 20 VLANS and only wants all to communicate with 1 VLAN fully and 19 others doesn't needs to communicated with each other.
Although in my case i have 4506, still i have'nt proceeded as ACL's will put a load on the CPU . Any idea ?
thanks,
Shakeel Ahmad
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