Access internet config at switch

[interfacedy]

hi Please see the below diagram. The PC99 has two adapters. One is A1 connected to internet via a router, and second is A2 is connected to the layer 3 switch. Internet share is configured at A1. 

internet -----R----(A1)PC99(A2) ------Switch.

A1 has private ip address 192.168.10.10. A2 is 10.0.10.1/24. The switch has vlan 10 with ip address 10.0.10.10/24 and vlan 20 with ip address 10.0.20.10. Another two PCs, PC1 and PC2, are plugged into the switch. The two PCs are connected to vlan 10 and vlan 20 respectively and the both PCs can ping each other. PC1 can ping internet, but PC2 cannot ping internet. Do you think if we need to add nat at the switch to let PC2 reach internet? Second question is what other way we can resolve the issue without changing config at the router? Thanks

[Reza Sharifi]

Hi,

Most Cisco switches don't do NAT. So, you would have to configure a NAT statement on the router for vlan 20 with IP subnet 10.10.20.0/24 so it can reach the Internet.

Second question is what other way we can resolve the issue without changing config at the router?

If you can't configure NAT, you can then put the second PC in the same subnet as the first one.

HTH 

[balaji.bandi]

By Nature Switch(basic switch)  not do any network address translation, in your case R does the all natting, since you mentioned Switch IP can able to reach the internet.

There are 2 Options :

1. Make the switch as Layer 2 only. ( so users get 192.x.x.x IP so Router does the NAT)

2. Add 10.x.x.x  network in Access in the router so router Nat the IP address.  (make sure you do static Route back 10.x.x.x network towards Switch IP address )

[interfacedy]

Thanks. but router is a device where config cannot be changed. 

[balaji.bandi]

but router is a device where config cannot be changed.

in that case, you have only one option here is Make PC99 Act as NAT Router  ( Apologies my Past post, i as in Impression PC99 (as Switch)

PC99  - is this Windows or Linux?