Query on default gateway with DHCP vs Static address

[Peter Yardley]

Hi,

This is prolly a problem with your configuration. Are you using ISC DHCPd? If so could provide a relevant snippet of your configuration, anonymised if necessary.

I used to configure subnets like this …

subnet 10.20.50.0 netmask 255.255.254.0 {
    option subnet-mask 255.255.254.0;
    option broadcast-address 10.20.51.255;
    option routers 10.20.50.1;

    pool {
        # A device for Blah
        host HMTXYZ           { hardware ethernet 00:40:9d:54:4c:c7;
                                        fixed-address 10.20.50.32; }
        …

        range 10.20.51.0 138.25.51.254;
    }

Of course there are many other correct possiblities


> On 19 Mar 2021, at 10:03 am, SIMON BABY <simonkbaby at gmail.com> wrote:
> 
> Hi,
> I have a query about the DHCP provided IP address vs Static IP address configured manually.  When i get the IP address from DHCP, I can ping to 8.8.8.8 (google public server) where as
> with a statically configured IP address, I could not.  When I looked into the route table (route -n ), I did not see any default gateway with DHCP or Statically configured IP.  (I am testing with Linux).
> 
> 1. Can I know when the packet goes out , how did the hardware (NIC) find the default gateway in the case of the DHCP provided IP address since I did not see any default gw IP in the routing table?
> 2. With statically configured IP, if I explicitly configure a default GW, I can see packets are going out and receiving. I can see the default GW in the routing table. Do I need a default GW to send packets from a statically configured IP address ?
> 
> Thank you for your time
> 
> Regards
> Simon
>  
> _______________________________________________
> ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.
> 
> dhcp-users mailing list
> dhcp-users at lists.isc.org
> https://lists.isc.org/mailman/listinfo/dhcp-users

Peter Yardley
peter.martin.yardley at gmail.com