Our ISP upgraded our cablemodem to a Cisco DPC3000 to support higher internet speed. I replaced our old modem with the new one and now I get no DHCP leases in my mikrotik rb750gl. If I connect a laptop and configure the ethernet por for DHCP, it works without a flaw. However, the mikrotik router gets stalled in the “searchig…” state.
It is interesting to note that during the startup of the modem, the mikrotik router gets a lease for IP address 192.168.100.20, which is lost 20 seconds after.
I’ve tried several ethernet port parameters (with/without autonegotiation, with/without full duplex, 10,100,1000). If I leave it in the default setup, I get 1 Gbps FD autonegotiated.
BTW, I can look the traffic in the interface using torch, and I see 10kbps of incoming traffic of bootpc and bootps protocols.
It sounds like the modem has locked on to your mac address of your computer. You could call the ISP and have the flush the ARP on the modem or copy the mac address from your computer to the ether port on your router connected to your modem.
That was my first impression. I used a second laptop to be sure that it wasn’t a MAC issue, and the second laptop worked without a flaw. I power cicle the modem after I change the device connected to it, to make it flush the arp cache.
Got it! The MAC address was the key. We have a fixed IP address and the provider messed the configuration when changing the cablemodem. It was working with all the MACs except our own’s
I changed the MAC address (substituted the last digit) and I got a dynamic IP.
Thanks very much for your kind help. Next time I’ll blame my ISP before posting
