Remove the unspecified gateway from linux routing table

Simon Hobson simon at thehobsons.co.uk
Tue Feb 17 11:23:38 UTC 2015


Patrick Trapp <ptrapp at nex-tech.com> wrote:

> Perhaps I am not completely awake yet, but don't you have to have the default gateway in place to have network communication? That is, doesn't it have to precede the DHCP process?

No, as I read it, he can see that the DHCP client has obtained a default route from the DHCP server, but for some reason 1) the DHCP client hasn't configured it, and 2) the device has a bogus default route. A client configured by DHCP (normally) gets it's default route by DHCP - ie there is no need to specify a static route, and in general doing so is "a bad idea" as it will break the network if the device roams.

But back to the OPs question ...

How the client configures the network is a distribution specific process. There will be a number of scripts bundled in the distro package that the client calls to configure stuff. My best guess is that there is a bug here and possibly the script is using 0.0.0.0 instead of the IP obtained by the DHCP client - either it isn't getting passed, or it's getting passed but getting 'lost' by the script.
It would be useful to prevent the client getting a lease and see what the routing table is then. If the 0.0.0.0/0 via 0.0.0.0 route is missing, but then appears when a lease is obtained, then it would suggest it's the DHCP client/script adding it.

To go any further would need details of the distribution in use - not just "a GNU/Linux system" !



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