I have a RB1200 running 6.11 -though the problem was also being experienced on 6.7, on which i am using DHCP client on VLAN 10, so as to get an IP address and default route for internet connectivity. The lease time on the address that is allocated to my device is 1800sec (30mins) at exactly 15 minutes, my router issues a "renew" as expected.

The DHCP server at the far end sends an ack..

At this point my RB1200 appears to ignore this response and does a full DHCP discovery - i.e. broadcast. During this phase my route to the internet dis-appears, and any FTP, or connection that is active is broken with network un-reachables being sent by the router board. I assume that this is because during this period, I do not actually have an address.

My address assigned does not change, however every 15 minutes I loose complete connectivity.

Can anyone explain why this happening?

The following is the log output for dhcp-client. for the renew-then new request.

mar/23 09:58:22 dhcp,debug,state dhcp-client on BR-VLAN10 entering <renewing...> state
mar/23 09:58:22 dhcp,debug,packet dhcp-client on BR-VLAN10 sending request with id 912604905 to 203.94.42.1
mar/23 09:58:22 dhcp,debug,packet ciaddr = 203.94.42.253
mar/23 09:58:22 dhcp,debug,packet chaddr = D4:CA:6D:41:97:7F
mar/23 09:58:22 dhcp,debug,packet Msg-Type = request
mar/23 09:58:22 dhcp,debug,packet Parameter-List = Subnet-Mask,Classless-Route,Router,Static-Route,Domain-Server,NTP-Server,CAPWAP-Server
mar/23 09:58:22 dhcp,debug,packet Host-Name = "MikroTik"
mar/23 09:58:22 dhcp,debug,packet Client-Id = 01-D4-CA-6D-41-97-7F
mar/23 09:58:22 dhcp,debug,packet dhcp-client on BR-VLAN10 received ack with id 912604905 from 203.94.42.1
mar/23 09:58:22 dhcp,debug,packet ciaddr = 203.94.42.253
mar/23 09:58:22 dhcp,debug,packet yiaddr = 203.94.42.253
mar/23 09:58:22 dhcp,debug,packet chaddr = D4:CA:6D:41:97:7F
mar/23 09:58:22 dhcp,debug,packet Msg-Type = ack
mar/23 09:58:22 dhcp,debug,packet Address-Time = 1800
mar/23 09:58:22 dhcp,debug,packet Server-Id = 203.94.42.1
mar/23 09:58:22 system,info dns changed
mar/23 09:58:22 dhcp,debug,state dhcp-client on BR-VLAN10 entering <selecting...> state
mar/23 09:58:23 dhcp,debug,packet dhcp-client on BR-VLAN10 sending discover with id 4049649828 to 255.255.255.255
mar/23 09:58:23 dhcp,debug,packet flags = broadcast
mar/23 09:58:23 dhcp,debug,packet ciaddr = 0.0.0.0
mar/23 09:58:23 dhcp,debug,packet chaddr = D4:CA:6D:41:97:7F
mar/23 09:58:23 dhcp,debug,packet Msg-Type = discover
mar/23 09:58:23 dhcp,debug,packet Parameter-List = Subnet-Mask,Classless-Route,Router,Static-Route,Domain-Server,NTP-Server,CAPWAP-Server
mar/23 09:58:23 dhcp,debug,packet Host-Name = "MikroTik"
mar/23 09:58:23 dhcp,debug,packet Client-Id = 01-D4-CA-6D-41-97-7F
mar/23 09:58:24 dhcp,debug,packet dhcp-client on BR-VLAN10 sending discover with id 3066583329 to 255.255.255.255
mar/23 09:58:24 dhcp,debug,packet flags = broadcast
mar/23 09:58:24 dhcp,debug,packet ciaddr = 0.0.0.0
mar/23 09:58:24 dhcp,debug,packet chaddr = D4:CA:6D:41:97:7F
mar/23 09:58:24 dhcp,debug,packet Msg-Type = discover
mar/23 09:58:24 dhcp,debug,packet Parameter-List = Subnet-Mask,Classless-Route,Router,Static-Route,Domain-Server,NTP-Server,CAPWAP-Server
mar/23 09:58:24 dhcp,debug,packet Host-Name = "MikroTik"
mar/23 09:58:24 dhcp,debug,packet Client-Id = 01-D4-CA-6D-41-97-7F
mar/23 09:58:24 dhcp,debug,packet dhcp-client on BR-VLAN10 received offer with id 3066583329 from 203.94.42.1
mar/23 09:58:24 dhcp,debug,packet flags = broadcast
mar/23 09:58:24 dhcp,debug,packet ciaddr = 0.0.0.0
mar/23 09:58:24 dhcp,debug,packet yiaddr = 203.94.42.253
mar/23 09:58:24 dhcp,debug,packet chaddr = D4:CA:6D:41:97:7F
mar/23 09:58:24 dhcp,debug,packet Msg-Type = offer
mar/23 09:58:24 dhcp,debug,packet Server-Id = 203.94.42.1
mar/23 09:58:24 dhcp,debug,packet Address-Time = 1800
mar/23 09:58:24 dhcp,debug,packet Subnet-Mask = 255.255.255.0
mar/23 09:58:24 dhcp,debug,packet Router = 203.94.42.1
mar/23 09:58:24 dhcp,debug,packet Domain-Server = 202.74.33.77,202.74.33.93
mar/23 09:58:24 dhcp,info dhcp-client on BR-VLAN10 got IP address 203.94.42.253
mar/23 09:58:24 dhcp,debug,state dhcp-client on BR-VLAN10 entering <bound> state
mar/23 10:13:24 dhcp,debug,state dhcp-client on BR-VLAN10 entering <renewing...> state
mar/23 10:13:24 dhcp,debug,packet dhcp-client on BR-VLAN10 sending request with id 3066583329 to 203.94.42.1
mar/23 10:13:24 dhcp,debug,packet ciaddr = 203.94.42.253
mar/23 10:13:24 dhcp,debug,packet chaddr = D4:CA:6D:41:97:7F
mar/23 10:13:24 dhcp,debug,packet Msg-Type = request
mar/23 10:13:24 dhcp,debug,packet Parameter-List = Subnet-Mask,Classless-Route,Router,Static-Route,Domain-Server,NTP-Server,CAPWAP-Server
mar/23 10:13:24 dhcp,debug,packet Host-Name = "MikroTik"
mar/23 10:13:24 dhcp,debug,packet Client-Id = 01-D4-CA-6D-41-97-7F
mar/23 10:13:24 dhcp,debug,packet dhcp-client on BR-VLAN10 received ack with id 3066583329 from 203.94.42.1
mar/23 10:13:24 dhcp,debug,packet ciaddr = 203.94.42.253
mar/23 10:13:24 dhcp,debug,packet yiaddr = 203.94.42.253
mar/23 10:13:24 dhcp,debug,packet chaddr = D4:CA:6D:41:97:7F
mar/23 10:13:24 dhcp,debug,packet Msg-Type = ack
mar/23 10:13:24 dhcp,debug,packet Address-Time = 1800
mar/23 10:13:24 dhcp,debug,packet Server-Id = 203.94.42.1
mar/23 10:13:24 system,info dns changed
mar/23 10:13:24 dhcp,debug,state dhcp-client on BR-VLAN10 entering <selecting...> state
mar/23 10:13:25 dhcp,debug,packet dhcp-client on BR-VLAN10 sending discover with id 1134413848 to 255.255.255.255
mar/23 10:13:25 dhcp,debug,packet flags = broadcast
mar/23 10:13:25 dhcp,debug,packet ciaddr = 0.0.0.0
mar/23 10:13:25 dhcp,debug,packet chaddr = D4:CA:6D:41:97:7F
mar/23 10:13:25 dhcp,debug,packet Msg-Type = discover
mar/23 10:13:25 dhcp,debug,packet Parameter-List = Subnet-Mask,Classless-Route,Router,Static-Route,Domain-Server,NTP-Server,CAPWAP-Server
mar/23 10:13:25 dhcp,debug,packet Host-Name = "MikroTik"
mar/23 10:13:25 dhcp,debug,packet Client-Id = 01-D4-CA-6D-41-97-7F
mar/23 10:13:26 dhcp,debug,packet dhcp-client on BR-VLAN10 sending discover with id 1134413848 to 255.255.255.255
mar/23 10:13:26 dhcp,debug,packet secs = 2
mar/23 10:13:26 dhcp,debug,packet flags = broadcast
mar/23 10:13:26 dhcp,debug,packet ciaddr = 0.0.0.0
mar/23 10:13:26 dhcp,debug,packet chaddr = D4:CA:6D:41:97:7F
mar/23 10:13:26 dhcp,debug,packet Msg-Type = discover
mar/23 10:13:26 dhcp,debug,packet Parameter-List = Subnet-Mask,Classless-Route,Router,Static-Route,Domain-Server,NTP-Server,CAPWAP-Server
mar/23 10:13:26 dhcp,debug,packet Host-Name = "MikroTik"
mar/23 10:13:26 dhcp,debug,packet Client-Id = 01-D4-CA-6D-41-97-7F

I too am actually seeing this happen as well.

Does anyone one understand why this is happening? I don't want to just change the lease time to something higher, I'd like to understand why this is happening.


RB3011UiAS
V6.39.1