Switch allows DHCPDISCOVER but drops DHCPOFFER

SwOS
1

Hey guys!

I’m having a following setup:




All necessary screens are in this Imgur post: https://imgur.com/a/ysHthtK

(make sure you load all images:)

The problem:

  1. When I connect to WiFi_Family (SSID: Uppsala) i get IP assigned beautifully, no problems at all. Full DHCP(DORA) chain
  2. When I switch to Mgmt Wifi (SSID: Valhalla) my router receives DHCPDISCOVER and sends back DHCPOFFER but it never gets to my laptop back (Wireshark logs attached in Imgur post)

I’m actually out of ideas. Can anyone help me understand why switch forwards DHCPDISCOVERS over VLAN5 to my OPNsense router but drops DHCPOFFER?

2

Created extra VLAN 105 on OPNsense and UniFi Network so AP would tag the traffic. Added this VLAN to the Switch to VLANs tab and it works. I get the IP immediately

The problem is still with the VLAN 5.

3

Is the wired management computer getting a DHCP address from the Router? If so, the problem is almost certainly with the AP or the interface between the switch and the AP. Not knowing how the AP is configured, I would wonder if the issue is because you are sending untagged traffic to the AP from the switch. Is that the desired mode? I know on my Meraki APs, ALL the VLANs that become different SSIDs are tagged. The only untagged traffic is the Meraki management.

Also, on ports that will only have tagged traffic (port 24 & SFP1 in your case), I assign a dummy Default VALN ID. Avoids any confusion. That dummy VLAN is unique to that port and should never get used. I use numbers in the 3xyz range that are not otherwise used anywhere.

4

Perhaps there is some dhcp snooping configuration defined somewhere that needs to be reviewed.