DHCP not working after configuring vlans

dellpedellpe Member Posts: 16 ■□□□□□□□□□
So I had a fully functional network with dhcp running successfully.

I have a Cisco 1921 router and a switch. I have connected three pcs to the switch and also the dhcp server.
Now I want to put two pcs out of three onto a different vlan. But when I do that, the dhcp server is not on the same vlan anymore. So these pcs are not able to get ip addresses using dhcp anymore. If I put the switch interface connected to the server to the new vlan than other pcs will be on different vlan and the same problem will occur with those pcs. I tried putting the interface connected to the dhcp server into trunking mode but that did not help at all.

Any suggestions on fixing this are appreciated.

Comments

  • atorvenatorven Member Posts: 319
    Use the ip helper-address command on each sub-interface on the router pointing to DHCP server.
  • DeathmageDeathmage Banned Posts: 2,496
    dellpe wrote: »
    So I had a fully functional network with dhcp running successfully.

    I have a Cisco 1921 router and a switch. I have connected three pcs to the switch and also the dhcp server.
    Now I want to put two pcs out of three onto a different vlan. But when I do that, the dhcp server is not on the same vlan anymore. So these pcs are not able to get ip addresses using dhcp anymore. If I put the switch interface connected to the server to the new vlan than other pcs will be on different vlan and the same problem will occur with those pcs. I tried putting the interface connected to the dhcp server into trunking mode but that did not help at all.

    Any suggestions on fixing this are appreciated.

    this may be a silly question but do you have routing between the vlan's? - ie if you don't have routing, how will they know to communicate with the other?
  • ahahaahaha Registered Users Posts: 7 ■□□□□□□□□□
    Agree with Deathmage, you should check the VLAN between the Cisco 1921 router. If do so, put your answer or question share with us.
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