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I just got a layer 2/3 switch from Dell, S3048-ON with OS9 version 9.13(0.0)

I'm trying to route vlan 20's clients to my ISP to reach the internet in vlan 10

This is my exact configuration:

  • Port Gi 1/1 is vlan 10 with IP from ISP 10.1.1.2 and gateway 10.1.1.1
  • Ports Gi 1/2-2/48 are vlan 20 with subnet 192.168.0.x/24

What's the correct way to route my clients to the ISP? I tried various settings but I couldn't get the clients to access the internet after all

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    We need to see all of your configuration. There are too many things to go wrong --we'd just end up guessing.
    – Ron Trunk
    Dec 27, 2017 at 18:50
  • This is a top-of-rack switch, and I don't find any reference to it being able to NAT, which you probably need to connect to an ISP.
    – Ron Maupin
    Dec 27, 2017 at 19:12
  • @RonMaupin This Dell whitepaper mentions you can through PBR although it's an old version of the software so I wasn't able to reproduce the similar configuration en.community.dell.com/cfs-file/__key/…
    – Tek
    Dec 27, 2017 at 19:34
  • PBR is not NAT. You need to translate (NAT) your private addressing to public addressing to be able to communicate on the public Internet. PBR doesn't do that.
    – Ron Maupin
    Dec 27, 2017 at 19:35
  • @RonMaupin In that case I may have misunderstood the purpose of that document
    – Tek
    Dec 27, 2017 at 19:37

1 Answer 1

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That is a top-of-rack switch, and it doesn't have NAT. You need NAT to translate from your private addressing to the public addressing used on the public Internet.

PBR is routing based on your policies, but it doesn't do anything with your addressing. Routing is based on the destination address on the packet, but you need to change the source address of outgoing packets, regardless of how they are routed, and create a table so that replies can have the return destination changed to the originating address.

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  • Thanks, I'll spin up a Linux VM with iptables in that case. When I got this gifted to me I suppose I just assumed all layer 3 devices support NAT
    – Tek
    Dec 28, 2017 at 1:22
  • Actually, most layer-3 switches do not have NAT. Cisco claims that it requires a hardware assist to perform properly, and only the routers have that (except the 65xx switches).
    – Ron Maupin
    Dec 28, 2017 at 1:58

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