[ipxe-devel] Subnet mask doesn't work

Michael Brown mcb30 at ipxe.org
Fri Jun 26 19:11:23 UTC 2015

On 26/06/15 18:55, Josh Jameson wrote:
> I am having an issue where I need to provide /32 DHCP request where the
> gateway is outside the subnet.
> For example consider the following DHCP offer;
>   IP:
>   Netmask:
>   Gateway:
> iPXE doesn't seem to communicate right. It times out when trying to get
> a HTTP request at

That doesn't surprise me.  By specifying a subnet mask of, you are telling iPXE (or any other client) that there 
is one and only one IP address on that network, which is the 
address itself.  You have not provided any way for the client to reach

>If I boot the same machine and
> network config into Linux or Windows I can access the URL.

That _does_ surprise me.  I tested it just now: as expected, Linux fails 
to communicate with  (Specifically, it refuses to even add as the default gateway, since that address is not within the 
designated local network range of

I'm not sure what network topology you're actually trying to create.  Is 
the iPXE client in the same broadcast domain as the gateway (i.e. if you 
send a broadcast such as an ARP request from the iPXE node, do you 
expect it to reach the gateway)?  If so, then you are probably using a 
subnet mask of

See https://en.wikipedia.org/wiki/Subnetwork#IPv4_subnetting for some 
basic introduction to subnet masks.

Hope that helps!


More information about the ipxe-devel mailing list