Firewall blocks access to DHCP over GUEST Interface (vlan01)

[wikb]

Hello all,

I have installed the v24.1.6 and configured a Guest Network as described here: https://docs.opnsense.org/manual/how-tos/guestnet.html
However, the clients cannot connect. They don't get an IP address, because the access to ISC DHCPv4 on GUEST Interface is blocked by Firewall Rule "Default deny / state violation rule". The automatically generated rules for access to DHCP server on GUEST Interface are available and active. But in the Firewall log i see

- - - - - - -
action    [block]
...
interface   hn0
interface_name   lan
...
dst    255.255.255.255
dstport   67
...

src    0.0.0.0
srcport   68
- - - - - - -

The GUEST Interface is opt1 (vlan1).

The DHCP request coming in as hn0 (lan) and not as opt1 (vlan1) interface. Why?
Can somebody give me a tip, what can be false?


The same procedure with old v22 worked great.

[netnut]

The DHCP request coming in as hn0 (lan) and not as opt1 (vlan1) interface. Why?
Can somebody give me a tip, what can be false?

You need to check your VLAN tagging, not specified in your post, but using Virtualization ?

With the search you can find a lot of information (do's and dont's) about VLAN configuration. Quick tip: don't use VLAN1 on OPT1 but choose another ID and configure your virtual switch accordingly.


 

[wikb]

Yes, it is a virtual machine, currently on Hyper-V. My previous "successful" setup with OPNsense v22 was running on ProxMox.

I try to search about VLAN and virtual switch configuration. Thank you for your reply.

[wikb]

I added another network adapter to the VM and set my VLAN there. Connect the GATS interface in the OPNsense to the adapter and it works. Thanks @netnut