Just wanted to ask some questions regarding on our project. I have a layer 3 switch having vlan10 - 120, 4 ports per vlan and assigned class C IP's, however due to lack of IP addresses it can only accommodate up to vlan70 so I decided to use class A IP's on vlan80-120 but it's not working, need your help guys on how to make this thing work. Thanks!
You need to use NAT to translate the private IP addresses to public addresses in order to route traffic from private addressing to the public Internet. You will need to set aside some public address space to be used for the public side of the NAT. Unfortunately, it is unlikely that you will be able to use NAT on a switch; you will probably need to use a router for that.
As something of an ISP, you really should not use RFC 1918 address space for your private addressing. RFC 6598, IANA-Reserved IPv4 Prefix for Shared Address Space, allocates the
100.64.0.0/10 address block for ISPs to use as shared address space in order to not conflict with the RFC 1918 address space used by the customers.
Ok so I'll go and assume you mean you are not able to access the one subnet from the other. Since I don't know what switch you are using I'll only be able to guess the following: You have no routing enabled ..?
On Cisco you will need to add
SVIs in those
VLANsand assign them an IP-Address. After that you will need to activate routing with
ip route and you're golden.
Not much more we can help here without some proper infos