I'm trying to setup a 48 ports gigabit switch (netgear GS748T).

My goal is to split the 48 ports to 3 vlans :

  • VLAN10 ports 2-20
  • VLAN20 ports 21-30
  • VLAN30 ports 31-46

What i did is :

  • On VLAN1, TAG port 1, UNTAG every other ports
  • On VLAN10, TAG PORTS 2-20, UNTAG every other ports
  • On VLAN20, TAG PORTS 21-30, UNTAG every other ports
  • On VLAN30, TAG PORTS 31-46, UNTAG every other ports

I didn't touch the PVID configuration page; don't know what this is.

Now, if i plug a cable to port 5, i can ping VLAN20 and VLAN30; same for VLAN20 i can ping VLAN10 and VLAN30.

What am I doing wrong here ? I'm quite new to VLANs ...

edit: VLAN10 is WAN (connected to firewall interface x0, public subnet/26) VLAN20 is MGMT (connected to firewall interface x4, 10.0.0.x/24)

Whenever i plug from firewall to vlan20 i see all ports of the switch go crazy and i have packet loss when pinging switch or accessing his web ui.

  • You definitely don't want more than one VLAN untagged on a single port! Jun 29, 2013 at 6:37

1 Answer 1


do you want to have any trunk-port [port that combines more than one vlan] or do you just want to have total traffic separation for three groups?

if the second - i suggest you:

  • leave port 1 as it is for experimentation
  • set up vlan10 - port 2-20 untagged, all other ports blank [not member]
  • set up vlan20 - ports 21-30 untagged, all other ports blank [not member]
  • set up vlan30 - ports 31-46 untagged, all other ports blank [not member]
  • Ideally, yes i'd like to have ports than can be member of multiple vlans.
    – Disco
    Feb 26, 2012 at 9:44
  • also, switch has an IP address that is part of the vlan10 (wan)
    – Disco
    Feb 26, 2012 at 9:45
  • i want to be able to access the switch admin ip from port 1 (when i'm in datacenter) and from wan (vlan10)
    – Disco
    Feb 26, 2012 at 9:47
  • edited question: added firewall
    – Disco
    Feb 26, 2012 at 9:57
  • i'm not sure if it'll be possible to manage the switch from two different vlans [port 1 in vlan 1 and some port on vlan10]. making switch reachable from the internet is not a very good idea [from the security perspective].
    – pQd
    Feb 26, 2012 at 10:43

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.