Can't delete a route with 0.0.0.0 gateway

I'm trying to set up my routes in a way that will allow me to connect to Vagrant box of Solum demo.

My routing table contains, but is not limited to, following routes:

$ route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.0.0 0.0.0.0 255.255.255.0 U 9 0 0 wlan0
192.168.76.0 192.168.76.2 255.255.255.0 UG 0 0 0 vboxnet0
192.168.76.0 0.0.0.0 255.255.255.0 U 0 0 0 vboxnet0

I'm suspecting the third route (automatically generated on Vagrant box startup) is interfering with the second route (created manually), so I'm trying to delete it.

However, using either of following commands

$ sudo route del 192.168.76.0 gw 0.0.0.0
$ sudo route del 192.168.76.0

returns:

SIOCDELRT: No such process

which usually pops up when route can't find the route.

On the other hand, using

$ sudo route del 192.168.76.0/24 gw 0.0.0.0
$ sudo route del 192.168.76.0/24

yields:

route: netmask 000000ff doesn't make sense with host route
Usage: route [-nNvee] [-FC] [<AF>] List kernel routing tables
(rest of usage)

What am I doing wrong? Is there a reason I can't remove that route? Am I wrong in assuming that it interferes with the one I set up?

(I'm using Ubuntu 14.04+).

2 Answers

To delete a single route from a route table, you need to specify enough parameters so a unique match with one of the routes can be made.

If you want to delete a whole subnet (as opposed to a single host) you need to both use the -net flag and some indication of the scope of the network address, i.e. either the netmask parameter (e.g. 255.255.255.0) or a number like /24 (meaning that the first 24 bits are the network number, and the remaining 8 are used for hosts). In your case, both

sudo route del -net 192.168.76.0/24

and

sudo route del -net 192.168.76.0 netmask 255.255.255.0

would have worked.

(thanks to @nephente for useful additions)

Comment made by Jos is almost correct:

$ sudo route del -net 192.168.76.0/24 removes the route.