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  • #2268995

    Multiple IP subnets

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    by sfjttgm ·

    Hi, I need some help. We received two set of IP ranges/blocks from our ISP for one location. We want to use both IP subnets on one 3750 Cisco switch that has one uplink to the ISP default gateway. Is it possible, to have both subnets with two LAN gateways IP configured on the same switch? Should we create two separate VLANs or is there other way to set up it up? Please show me how it is done? Thanks

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    • #2515512

      Clarifications

      by sfjttgm ·

      In reply to Multiple IP subnets

      Clarifications

    • #2515495

      put in a 2800

      by cg it ·

      In reply to Multiple IP subnets

      I would put in a 2800 between your ISP and the switches

      • #2515431

        Multiple IP subnets

        by sfjttgm ·

        In reply to put in a 2800

        Thanks. But we are using one of the ports as an uplink to the ISP already. The reason we have two IP subnets range is that we out grown the first set of IP range and we need more IP addresses. We want to continue to use the same 3750 switch for the new IP subnets.

        • #2517856

          well you can add them in the route table

          by cg it ·

          In reply to Multiple IP subnets

          as global local addresses but with many to one, one to many NAT allows less global local adresses hense lower cost than getting expensive public addresses from the ISP. Thats why I said to get a 2800. You can use NAT on the total WAN addresses you have so that hosts on subnets behind the router don’t need a public addresses.

          what do you have, a dedicated leased line or frame relay? certainly, most have a PIX or something in front of any WAN connection unless its a dedicated line.

          Again a router with NAT will solve your problem .

        • #2517812

          Multiple IP subnets

          by sfjttgm ·

          In reply to well you can add them in the route table

          Yes, but for this situation, we are not using NAT. All the servers are using public IP. And weird enough we are not using PIX for a reason for this setup. We have upgraded the network to a layer3 switch to save rack space and IP addresses.

        • #2517804

          save rack space and addresses?

          by cg it ·

          In reply to Multiple IP subnets

          7′ racks and cabinets can hold a lot of stuff.

          saving addresses…NAT saves you addresses no matter which way you look at it.

          All I can say is put your new pool into your layer 3 switch route table. you can’t use VLANs on the same switch unless you can route between them [well with a layer 3 device you could]you could trunk VLANs on seperate switches, but thats all a lot of work and admin effort that could be avoided with a layer 3 device with NAT

        • #2517796

          Multiple IP subnets

          by sfjttgm ·

          In reply to save rack space and addresses?

          I understand. Thanks

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