dhcp client get more than one IP address

RouterOS General
1

HI,

I use a routerboard RB750 as DSL gateway, the RB750 hase two connected interfaces: one to the modem (configured as bridge) second is connected to the local network.
the modem connected interface is configured as dhcp client (let’s say it is named ether1)in order to get the public address from ISP this configuration is well known and works great. the problem i’m facing now is that the ether1 is getting two dynamic ip addresses from the ISP: one public for the pppoe interface and one local for the ether1 itself, it seems that the ISP is having another dhcp server connected to the network that deliver local IPs.
the internet connection is no more working du to the fact that the default route and peer dns point to local address: i solved this problem by un-checking these 2 parameters (add default route, use peer dns) from dhcp client but got a worse problem: sometimes by some costumers the given dynamic local IP address is in the same subnet as the local network and i can’t ask the costumer to change his subnet.
the question is how to solve this problem: or how to limit the dhcp client to take only one public ip adresses?

thx for the help

2

I guess your ether1 is not only configured to run pppoe client (with dhcp-client) but your port is also member of the bridge were the local dhcp-server is serving IP addresses.
Check your port member ships on your local bridge or hour master-port settings

3

Hi,

thank you for your answer, but this is not the case, there is absolutely no bridge and nothing in bridge ports.

also because i don’t have dhcp server locally servicig this subnet

thx

4

Or more likely (If I understand you correctly) the modem in bridge mode still has DHCP server turned on. log into the modem interface and make sure DHCP is turned off in the modem.