why i should disabled local area connection while i connected to usb modem?

[wildan_ali]

i tried on windows7 and winXP to connect usb modem, and lan too on one pc..
but why i should disabled local area connection while i connected to usb modem?
i can't connect to LAN with it..so what i have to do?help me..

 

[jsmithepa]

It has to do with ROUTING (think of a traffic cop). LAN and USB modem now provides you with TWO ways to get out, the machine needs to know in which order things go and where is INTERNET GATEWAY (door by which you go through in order to get to the Internet).

When you enable LAN (ethernet) this typically gets an IP from the DHCP and at the same time a DEFAULT GATEWAY (same as Internet Gateway), but your Internet is now on USB isn't it? So one way to solve this is, tell DHCP "do not give me a DEFAULT GATEWAY." I do no know if your particular DHCP server has that capability. You can always use static IP on the ethernet that way you will have total control.

 

[wildan_ali]

It has to do with ROUTING (think of a traffic cop). LAN and USB modem now provides you with TWO ways to get out, the machine needs to know in which order things go and where is INTERNET GATEWAY (door by which you go through in order to get to the Internet).

When you enable LAN (ethernet) this typically gets an IP from the DHCP and at the same time a DEFAULT GATEWAY (same as Internet Gateway), but your Internet is now on USB isn't it? So one way to solve this is, tell DHCP "do not give me a DEFAULT GATEWAY." I do no know if your particular DHCP server has that capability. You can always use static IP on the ethernet that way you will have total control.

thank you before for your attantion and kind solution, but i use dhcp server in mikrotik. and in other case there's no problem so far if i connect usb modem and LAN at the same time..and the gateway from usb it's not same with my dhcp..is there a setting that is less in the local area connection or something else ?

 

[jsmithepa]

All I know is, if you drop to DOS and do a ROUTE PRINT (when you have both connected),

toward the bottom, it says DEFAULT GATEWAY IP, and if IP doesn't point to your USB NIC, or the next hop address which your USB modem is connected to, that's why it doesn't work.

Also when you have 2 NICs, they should be on different subnets.