Can someone explain me what is a non rout-able vlan, and when/why situation I will need it?
as far as I know it's a vlan that won't assign IP automatically, and only devices in the same vlan can see each other, but not from outside to inside, or from inside to outside. am I wrong? if not then when would I need it?
thanks
A non routeable VLAN is simply a normal VLAN that lacks a router, thereby not being routable to other networks.
One common use of non-routable VLANs is for storage networks. Servers are configured with multiple network connections, via VLAN trunking or multiple physical NICs, so that they can talk to any application networks that they need to, while being able to talk to their "protected" storage VLAN over the alternate interface.
It would be perfectly acceptable to have a DHCP server within a non-routeable VLAN; it will serve IP information etc, but will not give out a gateway.
It's not clear to me what it is you're asking, but I'm going to make a few points:
A VLAN is a layer 2 construct. Technically there's no such thing as a routable VLAN.
A VLAN (again a layer 2 construct) doesn't have anything to do with ip address assignment, DHCP or anything else at layer 3.
When you say routable VLAN I suspect what you really mean are hosts connected to ports in a particular VLAN that have Layer 3 connectivity and communication with hosts outside of their VLAN. This is accomplished at layer 3 via routing, either with a router or a Layer 3 switch configured for routing.
A Non-Routable VLAN is an Internal VLAN that can not access any Internal or external network(s). It is only accessible to the entity that has devices connected. Basically a closed loop within the Network you are connecting.
