Force DHCP server to send option to client

RouterOS General
1

I’m using a MikroTik DHCP server, and want to send DHCP option 43 to all clients, even those that did not request it in their Parameter-Request option. I’m trying to send “ANDROID_METERED” to clients to indicate to them that this hotspot is uplinked via 3G. Although Androids will act on a DHCP offer containing “ANDROID_METERED” in option 43 (the AP is set as a “mobile hotspot” under data usage from v4.0), they do not request it.

Is there any way to do this? The documentation http://wiki.mikrotik.com/wiki/Manual:IP/DHCP_Server#DHCP_Options suggests pretty clearly that…

According to the DHCP protocol, a parameter is returned to the DHCP client only if it requests this parameter, specifying the respective code in DHCP request Parameter-List (code 55) attribute. If the code is not included in Parameter-List attribute, DHCP server will not send it to the DHCP client.

…but I’m hoping there is some way around this.

Thanks.

Feature request: Force sending of DHCP options to clients
2

Hello,

This is indeed doable using ISC DHCP server, for instance:

if exists dhcp-parameter-request-list {

Always send the PXELINUX options (specified in hexadecimal, ie: 208 = 0xd0, 209 = 0xd1, etc.)

option dhcp-parameter-request-list = concat(option dhcp-parameter-request-list,d0,d1,d2,d3);
}

forces PXELINUX options to be sent.

(see http://www.syslinux.org/wiki/index.php/PXELINUX#Can_I_send_information_to_PXELINUX_via_special_options_in_the_DHCP_response.3F)

It would be nice Mikrotik dhcp server provides that feature as well, since it is also useful for major software like PXELINUX.