internet distribution

[suthomas1]

Hi,

Is it possible to  connect a 6500 switch to an adsl router for internet connectivity. the adsl router will be having dhcp ip.

should i configure the 6500 uplink port as L3 or L2 to connect to this router and how will the nat happen for users.

thanks in advance.

[Marwan ALshawi]

as long as you put a ethernet port into the 6500 then you can use either L3 routed interface or L2 interface with 3 VLAN interface in the same subnet of the ADSL LAN interface with default route configured point to the ADSL LAN IP

hope this help

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[suthomas1]

thank you. imagine i create four vlans 100, 200 ( 192.168.100.x , 192.168.200.x )and i use a small subnet vlan 150 (192.168.150.0/28)  specially to link the switch with this router, how should i control which vlan is allowed access to this adsl internet.

thanks.

[Marwan ALshawi · Accepted solution]

ok

if you this is the case then the Switch will take care of routing the traffic to the Internet once you add the static default route point to the ADSL LAN IP such as

ip route 0.0.0.0 0.0.0.0 192.168.150.x

however there is something you need to be aware of which is the NATing

normally simple/basic ADSL routers perform NATing to the traffic sourced from their LAN subnet range in your case the 192.168.150.0/28 which means any traffic from other vlans will not get Internet access due to this limitation

this is assumption you need to check this point and if the router can perfrom NATing for traffic from any source or multiple sources

if it is still the limitation in this case you have to configure NATing in the 6500 to let the ADSL router see the traffic from other vlans looks like config from the 6500 VLAN 150 interface

example

lets say you want to allow only vlan 200 to get acess to the internet with the NAT config:

acess-ist 100 permit ip 192.168.200.0 0.0.0.255 any

ip nat inside source list 100 interface vlan150 overload

int vlan 200

ip nat inside

int vlan 150

ip nat outside

if yo want vlan 100 to be included too

add additional line to ACL 100 above with vlan 100 network/subnet

hoep this help

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