DHCP server for virtual AP does not offer gateway, DNS, etc.

Hello,

I’m setting up a MikroTik for the first time, for a small office configuration.

I’d like to set up an internal network with the LAN ports and a WPA-protected WiFi interface, and another public network for guests with open WiFi that only has access to the Internet.

Ethernet and internal WiFi are working OK.

For the public WiFi, the DHCP server is acting strangely. I can see my DHCP requests and its offers, but my client (a Mac laptop) will not accept the offers. The offers do not include these important fields: Subnet-Mask, Default-Gateway, Domain-Name-Server, and I suspect that’s the reason my client won’t accept them.

I do see these fields from the internal WiFi. Its offers look something like this:

11:30:13.066598 IP (tos 0x0, ttl 16, id 0, offset 0, flags [none], proto UDP (17), length 328)
    192.168.88.1.67 > 192.168.88.251.68: BOOTP/DHCP, Reply, length 300, xid 0xc2cb99bc, Flags [none]
	  Your-IP 192.168.88.251
	  Server-IP 192.168.88.1
	  Client-Ethernet-Address f8:1e:df:e6:19:54
	  Vendor-rfc1048 Extensions
	    Magic Cookie 0x63825363
	    DHCP-Message Option 53, length 1: Offer
	    Server-ID Option 54, length 4: 192.168.88.1
	    Lease-Time Option 51, length 4: 259200
	    Subnet-Mask Option 1, length 4: 255.255.255.0
	    Default-Gateway Option 3, length 4: 192.168.88.1
	    Domain-Name-Server Option 6, length 4: 192.168.88.1

The non-working offers from the public WiFi look like this:

11:25:49.127154 IP (tos 0x0, ttl 16, id 0, offset 0, flags [none], proto UDP (17), length 328)
    192.168.3.254.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 300, xid 0xc2cb99b9, Flags [none]
	  Your-IP 192.168.3.98
	  Server-IP 192.168.3.254
	  Client-Ethernet-Address f8:1e:df:e6:19:54
	  Vendor-rfc1048 Extensions
	    Magic Cookie 0x63825363
	    DHCP-Message Option 53, length 1: Offer
	    Server-ID Option 54, length 4: 192.168.3.254
	    Lease-Time Option 51, length 4: 259200

I’m a bit stumped about how to go about troubleshooting this. Any tips?

My configuration looks like this:

# nov/20/2012 13:21:48 by RouterOS 5.11
# software id = K43B-F322
#
/ip dhcp-server
add address-pool=default-dhcp authoritative=after-2sec-delay bootp-support=\
    static disabled=no interface=bridge-local lease-time=3d name=default
add address-pool=public-pool authoritative=after-2sec-delay bootp-lease-time=\
    forever bootp-support=dynamic disabled=no interface=wlan2 lease-time=3d \
    name=public-dhcp
/ip dhcp-server config
set store-leases-disk=5m
/ip dhcp-server network
add address=192.68.1.0/24 dns-server=192.168.1.254 gateway=192.168.1.254
add address=192.168.3.0/24 comment="default configuration" dns-server=\
    192.168.3.254 gateway=192.168.3.254

/ip address
add address=192.168.3.254/24 comment="default configuration" disabled=no \
    interface=bridge-local network=192.168.3.0
add address=192.168.1.254/24 comment="Public Wifi Virtual AP" disabled=no \
    interface=wlan2 network=192.168.1.0

/ip pool
add name=default-dhcp ranges=192.168.3.10-192.168.3.254
add name=public-pool ranges=192.168.1.10-192.168.1.254

My wireless interfaces look like this:

Flags: X - disabled, R - running 
 0    name="wlan1" mtu=1500 mac-address=D4:CA:6D:26:F4:45 arp=enabled 
      interface-type=Atheros 11N mode=ap-bridge ssid="GCMS-PRIV" 
      frequency=2412 band=2ghz-b/g/n channel-width=20/40mhz-ht-above 
      scan-list=default wireless-protocol=any antenna-mode=ant-a 
      wds-mode=disabled wds-default-bridge=none wds-ignore-ssid=no 
      bridge-mode=enabled default-authentication=yes default-forwarding=yes 
      default-ap-tx-limit=0 default-client-tx-limit=0 hide-ssid=no 
      security-profile=private compression=no 

 1  R name="wlan2" mtu=1500 mac-address=D6:CA:6D:26:F4:45 arp=enabled 
      interface-type=virtual-AP master-interface=wlan1 ssid="GCMS-PUB" 
      wds-mode=disabled wds-default-bridge=bridge-local wds-ignore-ssid=no 
      bridge-mode=enabled default-authentication=yes default-forwarding=yes 
      default-ap-tx-limit=0 default-client-tx-limit=0 hide-ssid=no 
      security-profile=public

The public WiFi is on wlan2, network 192.68.1.0/24.

Any help would be very much appreciated!

This line is wrong:

add address=192.68.1.0/24 dns-server=192.168.1.254 gateway=192.168.1.254

Correct one:

add address=192.168.1.0/24 dns-server=192.168.1.254 gateway=192.168.1.254

Thanks fxx! I must have looked right past that 100 times.

There seems to be something confused about the IP ranges. The public WiFi is supposed to be on 192,168,1.0/24 but is being offered IPs in range 192.168.3.0/24.

Note typo above mentioned above - possible cause or related?

If that doesn’t cure it upload output from /export compact.

I unfortunately blew out the public WiFi config in a tragic networking accident that required resetting the router. Before I got a response, I was able to get it to work by removing the entire DHCP configuration and re-entering it. Probably I avoided the typo the second time through and that’s why it worked.