Re: dhcpdump not seeing dhclient messages
On Mon, Aug 26, 2013 at 02:54:27PM +0530, Arun Khan wrote:
> On Mon, Aug 26, 2013 at 2:01 PM, Sean Alexandre <sean@alexan.org> wrote:
> > I have a machine that's not acquiring a DHCP lease from my ISP. I can see that
> > dhclient is sending DHCPDISCOVER messages. My system log has:
> >
> > Aug 25 17:36:41 athabasca dhclient: DHCPDISCOVER on eth-wan to 255.255.255.255 port 67 interval 7
>
> -------------8<-------------8<-------------8<-------------8<-------------8<-------------8<-------------8<-------------
>
> > The odd thing is if I do the exact same thing with this machine connected to
> > a local TP-LINK router instead of my ISP cable modem, dhcpdump sees the
> > DHCPDISCOVER, and the machine acquires a DHCP lease.
>
> Is your cable modem setup in bridge mode? (bridge between it's
> ethernet (RJ45) and the 'wan' ports with cable coming in from ISP.
Yes, bridge mode. (It's just a cable modem, and not a router. Bridge mode is the
only way it works.)
>
> > Any ideas why would dhclient be sending a DHCPDISCOVER, but dhcpdump not see it?
>
> Try tcpdump with dest port 67
OK, thanks. I just tried that now, and it got a DHCP lease this time, for some
reason. So it's working again. I'll do a tcpdump next time, if I see the
problem again, and hopefully that will tell me what's going on.
Reply to: