DHCP Relay changes in 3.15 ?
Posted: Tue Nov 04, 2008 1:37 am
I recently upgraded from an RB500 running v3.14 to an RB493 that I have at v3.15.
I have a WAP that acts as a DHCP Relay to my RB500, so that the RB500 can dole out DHCP Addresses. The configuration works fine.
I copied nearly the whole configuration over from the 500 to the 493 (the DHCP configuration is the same on both), and stood-down the RB500, sot he 493 is fully acting as a replacement for the original RB500.
The RB493, v3.14, will not answer DHCP-Relayed requests. It will answer DHCP requests from machines on any locally attached network, but not forwarded ones. Using wireshark and Tools/Packet-Sniffer, I can see the requests reach the Mikrotik, but nothing is sent back out. When I turn off the dhcp-server that handles the forwarded requests on the 493, I see the complaints in the MT's log about "received discover from xx:xx:xx:xx:xx:xx with unknown giaddr 192.168.201.253", so i know that the MT, itself "hears" the requests. But turning that dhcp-server back on, the complaints go away (as they should) but there is no response outbound.
There are no packet-filters in the OUTPUT chain.
Did anything change in the DHCP-Server code between v3.14 and 3.15 ??
Thanks in advance,
--------------------------
ok, to answer my own question on this, this is definitely a behavior change from v3.14
the "/dhcp-server" line for the dhcp server that the relay is relaying to, now needs a src-address= parameter that matches the IP address that the relaying server relayed the request to.
Up til the previous release, this parameter wasn't required.
Problem solved...
I have a WAP that acts as a DHCP Relay to my RB500, so that the RB500 can dole out DHCP Addresses. The configuration works fine.
I copied nearly the whole configuration over from the 500 to the 493 (the DHCP configuration is the same on both), and stood-down the RB500, sot he 493 is fully acting as a replacement for the original RB500.
The RB493, v3.14, will not answer DHCP-Relayed requests. It will answer DHCP requests from machines on any locally attached network, but not forwarded ones. Using wireshark and Tools/Packet-Sniffer, I can see the requests reach the Mikrotik, but nothing is sent back out. When I turn off the dhcp-server that handles the forwarded requests on the 493, I see the complaints in the MT's log about "received discover from xx:xx:xx:xx:xx:xx with unknown giaddr 192.168.201.253", so i know that the MT, itself "hears" the requests. But turning that dhcp-server back on, the complaints go away (as they should) but there is no response outbound.
There are no packet-filters in the OUTPUT chain.
Did anything change in the DHCP-Server code between v3.14 and 3.15 ??
Thanks in advance,
--------------------------
ok, to answer my own question on this, this is definitely a behavior change from v3.14
the "/dhcp-server" line for the dhcp server that the relay is relaying to, now needs a src-address= parameter that matches the IP address that the relaying server relayed the request to.
Up til the previous release, this parameter wasn't required.
Problem solved...