6

I have a device which runs a DHCP server. When I connect it with USB to my computer, the PC gets an IP address and the device becomes the default gateway. I just want the device to agree on IP addresses and not default gateway. Is this possible?

I was using udhcpd but I got problems with authoritative mode so I switched to dnsmasq.

The PC is already connected to another network witch should contain the default gateway.

EDIT :

Here is a little diagram of how it is setup

[ Embedded Network #1 ] ----- [ PC ] ----- [ Corporate Network #2 ]

What is important here is that Net#1 has no knowledge of Net#2, its dhcp server and its default gateway

EDIT 2 :

Ok, the parameter in /etc/dnsmasq.conf should be about dhcp-option=3
If I don't specify this parameter well, there is no effect. According to this example config.

# Disable default gateway
#dhcp-option=3

This does not disable the gateway, this has no effect

EDIT 3 :

ok dhcp-option=3 DOES have an effect (Silly me). However just renewing ip is not enough for windows xp to forget about the old one

2
  • May I ask what did you do for Windows to forget about the old one?
    – sayap
    Sep 14, 2012 at 4:14
  • Although being a little late, just for the reference, you can use ipconfig /release followed by a ipconfig /renew to make Windows forget about the old settings.
    – buergi
    Feb 23, 2015 at 18:15

1 Answer 1

4

Certainly possible - just reconfigure the device to not hand out a gateway over DHCP.

You probably need to provide more information to get a useful response.

add to the conf file

dhcp-option=3
dhcp-option=6

3 disables default router (gateway) and 6 disables DNS

7
  • What kind of information?
    – user1190
    Jul 4, 2011 at 13:54
  • What's the device? Can you reconfig dhcp on it? Or is this enough?
    – MikeyB
    Jul 4, 2011 at 13:55
  • It is a custom embedded device which runs linux. I can cross compile a lot of stuff for ARM for it. I can of course edit configs
    – user1190
    Jul 4, 2011 at 14:06
  • You need to change DHCP option 3 (Router) to point to your router. DHCP is often handled by the router, so is is usually to have the DHCP configuration to default the router setting to its address.
    – BillThor
    Jul 4, 2011 at 14:10
  • Bill, I edited my question. The device network does not know the other network
    – user1190
    Jul 4, 2011 at 14:16

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .