05-18-2023 08:29 AM
Hi,
i have the following issue, Guest Vlan 40, getting ip from dhcp and all working fine, except internet.
Vlan 40 should be only accces internet.
any help would be really appreciated
attached my config
thanks
05-18-2023 08:39 AM
Hi,
What type of device is this? Most small Cisco switches do not support NAT. If this is the case, you need a router or a firewall to perform NAT function.
HTH
05-18-2023 08:56 AM
C1111X Router
05-18-2023 08:44 AM
Hi @m.yildiz ,
The Vlan 40 subnet is specifically denied in the access-list used for NAT.
ip access-list extended 100
10 permit ip 192.168.178.0 0.0.0.255 any
20 permit ip 10.10.10.0 0.0.0.255 any
30 permit ip 20.20.20.0 0.0.0.255 any
40 permit ip 30.30.30.0 0.0.0.255 any
50 deny ip 40.40.40.0 0.0.0.255 any
60 permit ip 50.50.50.0 0.0.0.255 any
70 permit ip 60.60.60.0 0.0.0.255 any
!
Regards,
05-18-2023 08:57 AM
how to correctly do the acces list?
05-18-2023 09:29 AM - edited 05-18-2023 09:36 AM
Hi @m.yildiz ,
To fix the issue you need to permit the Vlan40 subnet, like the other subnets in the access list. You can do the following:
config t
no ip access-list extended 100
ip access-list extended 100
10 permit ip 192.168.178.0 0.0.0.255 any
20 permit ip 10.10.10.0 0.0.0.255 any
30 permit ip 20.20.20.0 0.0.0.255 any
40 permit ip 30.30.30.0 0.0.0.255 any
50 permit ip 40.40.40.0 0.0.0.255 any
60 permit ip 50.50.50.0 0.0.0.255 any
70 permit ip 60.60.60.0 0.0.0.255 any
!
Regards,
05-18-2023 09:38 AM
that means, vlan can reach the other vlans, which should not be
vlan40 guest vlan, only internet acces
05-18-2023 09:50 AM
Hi @m.yildiz ,
access-list 100 is strictly used for NAT purpose. There is no access-list to control traffic between the vlans. So if the intent was to prevent vlan40 subnet to communicate with the other vlans then it was the wrong way.
Regards,
05-18-2023 09:53 AM
HI,
any suggestions?
How to solve ?
Thanks
05-18-2023 10:07 AM
Hi @m.yildiz ,
You could add an inbound access-list on interface vlan40 to prevent it from accessing the other local vlans and allow everything else. It would look something like this:
interface vlan40
ip access-group 101 in
!
ip access-list extended 101
10 deny ip any 192.168.178.0 0.0.0.255
20 deny ip any 10.10.10.0 0.0.0.255
30 deny ip any 20.20.20.0 0.0.0.255
40 deny ip any 30.30.30.0 0.0.0.255
50 deny ip any 50.50.50.0 0.0.0.255
60 deny ip any 60.60.60.0 0.0.0.255
70 permit ip 40.40.40.0 0.0.0.255 any
!
Regards,
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