Question: I have the following routes that I wish to delete:

```
10.250.0.0           10.250.0.37          UG        1          0

```

I have run the following to delete this with failure.

```
bash-3.2# route delete 10.250.0.0 -netmask 255.255.255.0 10.250.0.37
delete net 10.250.0.0: gateway 10.250.0.37: not in table

```

What is the cause for that failure?

Answer: 
For the Solaris `route` command, the delete, and add, sub-commands have the following syntax:

```
  route [ -fnvq ] cmd destination gateway [metric/netmask]

```

So you probably have more success with: 

```
route delete 10.250.0.0 10.250.0.37 -netmask 255.255.255.0

```

Or to remove it permanently (as commented by @Alexandre Alves; assuming this was a permanent route):

```
route -p delete 10.250.0.0 10.250.0.37 -netmask 255.255.255.0

```

(Are you sure your netmask is correct for this class A ip-address?)
Don't forget the `-p` flag on your route command. This is what makes it persistent.

So rather than doing:

```
route delete 10.250.0.0 10.250.0.37 -netmask 255.255.255.0

```

you should be doing:

```
route -p delete 10.250.0.0 10.250.0.37 -netmask 255.255.255.0

```

If you don't use the `-p` flag when you delete then you'll just experience that the route is still there after you've rebooted (provided the route is persistent in the first place).

You can at any time see all routes with the `netstat -r` command and you can see persistent routes with the `route -p` command.