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S2500-48P-4x10G - Router Intervlan Routing

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  • 1.  S2500-48P-4x10G - Router Intervlan Routing

    Posted Sep 02, 2021 07:07 PM

    Yes.. I know older switch, but its what I have to work with.


    Looking for example of  use of L3 basic Inter-VLAN routing table.  VLAN ID is third Octet.   GW for environment is which is on wifi/ ISP router.

    Lab Diagram

    1) Goal is to get all VLANs to Route to each other. 
    2) Allow VLAN 100 to use GW
    3) If possible, allow hosts on each VLAN to route to internet direct (This means via IP which is IP of sw0 Aruba switch)

    I started writting up the route table for the switch and it was a bit of a mess.  Other switch vendors it is a setting to allow VLAN bridging and you just set GW on router (which is done and works fine on VLAN 100)

    As always. Thanks for help

    I can post my Route table attempt .. but its bad.   RTFM is fine.. just point me to the FM.

    Jeremey Wise

  • 2.  RE: S2500-48P-4x10G - Router Intervlan Routing

    Posted Sep 03, 2021 06:31 AM
    The chapter 18 in the MAS User Guide (L3-routing) should have all the information.

    Create VLAN interfaces, configure DHCP/DHCP-relay if your clients need to get an IP, configure the default route.
    Then make sure your SW2 can route back to the MAS for the VLANs 101-104 IPs, and that it performs NAT for those ranges as well.

    The MAS switch does support NAT as well, but I would leave NAT as close to the ISP as possible.

    Herman Robers
    If you have urgent issues, always contact your Aruba partner, distributor, or Aruba TAC Support. Check for how to contact Aruba TAC. Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or Aruba Networks.

    In case your problem is solved, please invest the time to post a follow-up with the information on how you solved it. Others can benefit from that.

  • 3.  RE: S2500-48P-4x10G - Router Intervlan Routing

    Posted Sep 03, 2021 12:29 PM
    I appreciate the response but that implies that SW2 which is a Wifi Netgear router, does all the inter-vlan routing.  The lab will have 4 VLANs but more dynamic VLANs if / as I set up demos.

    As such, what I would liked to have done is simply run a command such as Inter-VLAN Routing (  

    Or add some set of static routes without pushing all VLANs to use GW of Netgear
    (sw0) #show ip route

    Codes: C - connected
    O - OSPF, O(IA) - OSPF inter area
    O(E1) - OSPF external type 1, O(E2) - OSPF external type 2
    O(N1) - OSPF NSSA type 1, O(N2) - OSPF NSSA type 2
    M - mgmt, S - static, * - candidate default
    D - DHCP

    Gateway of last resort is to network at cost 1
    S * /0 [1] via
    C is directly connected: vlan100
    C is directly connected: vlan100

    (sw0) #

    90% of traffic will be VLAN 100  ( to internet , but to have routing would be very useful.

    Jeremey Wise

  • 4.  RE: S2500-48P-4x10G - Router Intervlan Routing

    Posted Sep 04, 2021 08:20 AM
    Hi Jeremy,

    "I appreciate the response but that implies that SW2 which is a Wifi Netgear router, does all the inter-vlan routing"

    No, on the contrary...what Herman suggested you it is to ENABLE the IP Routing at SW0 (Aruba Networking MAS S2500) level and it implies that the routing happens on SW0 for all of its VLANs: the SW0 will be the router for all its internal defined VLANs and the SW0 needs to have a Route of Last Resort (the classic static default route 0/0 via NHG) to your Netgear WiFi Router, the SW2 will then act as the Next Hop Gateway for your SW0.

    It's a matter of:
    (1) enabling IP Routing
    (2) setting the RoLR to SW2
    (3) Let SW2 (with static routes) to know how to reach your internal VLANs (via SW0)

    A Client of a VLAN segment (172.16.x.0/24) will use the VLAN SVI IP Address (172.16.x.254) as its Default Gateway, the routing between VLANs and to external networks will happen on SW0. The RoLR will route messages to external networks, the SW2 needs to know how to reply back to VLANs (so, in other terms, it needs to know that, as example, the VLAN 103 segment with subnet - can be reached through the and the same should be valid also for all other VLANs routed by the SW0).

    Clearly the above scenario implies that uplink between SW0 and SW2 is on both ends an untagged (or tagged, if you want) member of VLAN 100 since the SW2 has a foot inside VLAN 100 of SW0 (and you aren't using a dedicated Transit VLAN - a /31 subnet - for SW2-SW0 communication).

    Davide Poletto