First time posting so please bear with me…
I have a RB2011UiAS acting as a DHCP server for VDSL modems connected through a DSLAM. It seems the modem/routers are a little finicky about the DHCP responses they receive from the server. The modems send discover and request messages with the broadcast flag set to 0 but many times the server sends the offer and ack messages as broadcasts.
This is from the log:
00:50:22 dhcp,debug,packet Management_DHCP_Server received discover with id 1941582630 from 0.0.0.0
00:50:22 dhcp,debug,packet ciaddr = 0.0.0.0
00:50:22 dhcp,debug,packet chaddr = 3C:90:66:30:3F:78
00:50:22 dhcp,debug,packet Msg-Type = discover
00:50:22 dhcp,debug,packet Parameter-List = Subnet-Mask,Router,Domain-Server,Host-Name,Domain-Name,Broadcast-Address,Classless-Route
00:50:22 dhcp,debug,packet Relay-Agent-Info = 01-27-46-72-65-6D-6F-6E-74-4C-61-62-20-34-63-3A-61-63-3A-61-3A-63-33-3A-63-62-3A-64-36-20-65-74-68-20-32-2F-31-3A-31-30-30
00:50:22 dhcp,debug,packet Management_DHCP_Server sending offer with id 1941582630 to 10.202.0.99
00:50:22 dhcp,debug,packet ciaddr = 0.0.0.0
00:50:22 dhcp,debug,packet yiaddr = 10.202.0.99
00:50:22 dhcp,debug,packet siaddr = 10.202.0.254
00:50:22 dhcp,debug,packet chaddr = 3C:90:66:30:3F:78
00:50:22 dhcp,debug,packet Msg-Type = offer
00:50:22 dhcp,debug,packet Server-Id = 10.202.0.254
00:50:22 dhcp,debug,packet Address-Time = 21600
00:50:22 dhcp,debug,packet Subnet-Mask = 255.255.255.0
00:50:22 dhcp,debug,packet Router = 10.202.0.254
00:50:22 dhcp,debug,packet Domain-Server = 10.202.0.254
00:50:22 dhcp,debug,packet Relay-Agent-Info = 01-27-46-72-65-6D-6F-6E-74-4C-61-62-20-34-63-3A-61-63-3A-61-3A-63-33-3A-63-62-3A-64-36-20-65-74-68-20-32-2F-31-3A-31-30-30
00:50:22 dhcp,debug,packet Management_DHCP_Server received discover with id 1817835063 from 0.0.0.0
00:50:22 dhcp,debug,packet ciaddr = 0.0.0.0
00:50:22 dhcp,debug,packet chaddr = 3C:90:66:67:35:90
00:50:22 dhcp,debug,packet Msg-Type = discover
00:50:22 dhcp,debug,packet Parameter-List = Subnet-Mask,Router,Domain-Server,Host-Name,Domain-Name,Broadcast-Address,Classless-Route
00:50:22 dhcp,debug,packet Relay-Agent-Info = 01-27-46-72-65-6D-6F-6E-74-4C-61-62-20-34-63-3A-61-63-3A-61-3A-63-33-3A-63-62-3A-64-36-20-65-74-68-20-32-2F-33-3A-31-30-30
00:50:22 dhcp,debug,packet Management_DHCP_Server sending offer with id 1817835063 to 255.255.255.255
00:50:22 dhcp,debug,packet ciaddr = 0.0.0.0
00:50:22 dhcp,debug,packet yiaddr = 10.202.0.100
00:50:22 dhcp,debug,packet siaddr = 10.202.0.254
00:50:22 dhcp,debug,packet chaddr = 3C:90:66:67:35:90
00:50:22 dhcp,debug,packet Msg-Type = offer
00:50:22 dhcp,debug,packet Server-Id = 10.202.0.254
00:50:22 dhcp,debug,packet Address-Time = 21600
00:50:22 dhcp,debug,packet Subnet-Mask = 255.255.255.0
00:50:22 dhcp,debug,packet Router = 10.202.0.254
00:50:22 dhcp,debug,packet Domain-Server = 10.202.0.254
00:50:22 dhcp,debug,packet Relay-Agent-Info = 01-27-46-72-65-6D-6F-6E-74-4C-61-62-20-34-63-3A-61-63-3A-61-3A-63-33-3A-63-62-3A-64-36-20-65-74-68-20-32-2F-33-3A-31-30-30
This shows two different Discover messages from two identical devices. In one case the server responds with a unicast offer, in the other it sends a broadcast offer.
Running 6.41 right now but incremental upgrading from 6.35 to 6.41 all showed the same behavior. Attached is the config, it wouldn’t allow me to attach a pcap file showing the packets.
Any help here would be greatly appreciated.
Thank you very much.
LabConfig_1-14-18.rsc (2.92 KB)