DHCP replies not reaching WIFI clients

RouterOS Beginner Basics
1

Hi,

I’m trying to use a hAP ax lite as an access point with VLANs. I have one VLAN for DMZ (103), one for LAN (100) and one for guests (104). I set up a bridge with VLAN filtering and so the VLANs are accessible via ether2 (104), 3 (100) and 4 (100). DHCP works here. But my attempts at making VLAN 100 available via WIFI failed so far. In my main router (a RB5009) I can see that the DHCP requests from WIFI are received on the main router, the status column shows “offered”, but my Android phone never gets an address. Between the router and the hAP is a Cisco switch, but since DHCP works for wired clients, I’d rule him out as a suspect. I have a Ubiquiti AP which is configured conceptionally the same (guest and lan) and DHCP works in this setup normally.

# 2024-09-04 22:02:28 by RouterOS 7.15.3
# software id = xxxxxx
#
# model = L41G-2axD
# serial number = HExxxxxxxx
/interface bridge
add name=bridge1 protocol-mode=none pvid=103 vlan-filtering=yes
/interface wifi
set [ find default-name=wifi1 ] channel.band=2ghz-ax .frequency=2447 .width=\
    20/40mhz configuration.country=Austria .mode=ap .ssid=\
    myssid datapath.bridge=bridge1 .vlan-id=100 disabled=no \
    interworking.domain-names=some.net .internet=yes .network-type=private \
    .venue=residential-private mtu=1500 security.authentication-types=\
    wpa2-psk,wpa3-psk
/port
set 0 name=serial0
/interface bridge port
add bridge=bridge1 interface=ether1 pvid=103
add bridge=bridge1 frame-types=admit-only-untagged-and-priority-tagged \
    interface=ether2 pvid=104
add bridge=bridge1 frame-types=admit-only-untagged-and-priority-tagged \
    interface=ether3 pvid=100
add bridge=bridge1 frame-types=admit-only-untagged-and-priority-tagged \
    interface=ether4 pvid=100
/interface bridge vlan
add bridge=bridge1 untagged=ether1 vlan-ids=103
add bridge=bridge1 tagged=ether1 untagged=ether2 vlan-ids=104
add bridge=bridge1 tagged=ether1 untagged=ether3,ether4,wifi1 vlan-ids=100
/ip dhcp-client
add interface=bridge1
/system clock
set time-zone-name=Europe/Vienna
/system identity
set name=ap-buero
/system note
set show-at-login=no
/system routerboard settings
set auto-upgrade=yes

I’d be happy for any advice. I googled a lot and tried lots of stuff on the router (DHCP server Always broadcast), disabling RSTP on the AP’s bridge and reconfigured everything from scratch several times. I don’t know why DHCP doesn’t work for WIFI here…

Thanks, Andreas

2

Solved it. I don’t really know why bridge1 needs to be tagged member of itself, but thats what others did and I overlooked that…

/interface bridge vlan
add bridge=bridge1 tagged=ether1,bridge1 untagged=ether3,ether4,wifi1 vlan-ids=100

And I didn’t try if it’s possible to replace

/interface bridge port
add bridge=bridge1 frame-types=admit-only-untagged-and-priority-tagged interface=wifi1 pvid=100

with

datapath.bridge=bridge1 .vlan-id=100

of the wifi interface…

If somebody else has this problem, here is the complete config:

# 2024-09-08 21:20:40 by RouterOS 7.15.3
# software id = xxxx
#
# model = L41G-2axD
# serial number = xxxx
/interface bridge
add name=bridge1 pvid=103 vlan-filtering=yes
/interface wifi
set [ find default-name=wifi1 ] channel.band=2ghz-ax .frequency=2447 .width=\
    20/40mhz configuration.country=Austria .mode=ap .ssid=\
    myssid disabled=no mtu=1500 security.authentication-types=\
    wpa2-psk,wpa3-psk
/port
set 0 name=serial0
/interface bridge port
add bridge=bridge1 interface=ether1 pvid=103
add bridge=bridge1 frame-types=admit-only-untagged-and-priority-tagged \
    interface=ether2 pvid=104
add bridge=bridge1 frame-types=admit-only-untagged-and-priority-tagged \
    interface=ether3 pvid=100
add bridge=bridge1 frame-types=admit-only-untagged-and-priority-tagged \
    interface=ether4 pvid=100
add bridge=bridge1 frame-types=admit-only-untagged-and-priority-tagged \
    interface=wifi1 pvid=100
/ip neighbor discovery-settings
set discover-interface-list=!dynamic
/interface bridge vlan
add bridge=bridge1 untagged=ether1 vlan-ids=103
add bridge=bridge1 tagged=ether1 untagged=ether2 vlan-ids=104
add bridge=bridge1 tagged=ether1,bridge1 untagged=ether3,ether4,wifi1 \
    vlan-ids=100
/ip dhcp-client
add interface=bridge1
/system clock
set time-zone-name=Europe/Vienna
/system identity
set name=ap-buero
/system note
set show-at-login=no
/system routerboard settings
set auto-upgrade=yes