Cannot get Asus DSL-AC68U to add proper Gateway

michalis

Hi,
I have an Asus RT-AC56U (10.10.1.250) with an Open VPN server setup which adds DNS options for the domain controller at 10.10.1.1
interface type: TAP
Protocol UDP
with custom configuration:

push "dhcp-option DNS 10.10.1.1"
push "route 10.10.1.0 255.255.255.0"

This works fine with my Windows openvpn setup. But when I try and set this up on a router Asus DSL-AC68U with the following:

client
dev tap
proto udp
remote ******* 1194
float
cipher BF-CBC
comp-lzo adaptive
keepalive 15 60
ns-cert-type server

resolv-retry infinite
nobind

No routes are added. The logs show that there is a conflicted routing rule:

/sbin/ifconfig tap15 10.10.1.51 netmask 255.255.255.0 mtu 1500 broadcast 10.10.1.255
Ignore conflicted routing rule: 10.10.1.0 255.255.255.0

If I try and add the routes manually on the client side, by adding the following:

route-nopull
route 10.10.1.0 255.255.255.0 10.10.1.250

I get the following:

/sbin/route add -net 10.10.1.0 netmask 255.255.255.0 gw 10.10.1.250
ERROR: Linux route add command failed: external program exited with error status: 1

I'm not sure where to look on why the routing rules are failing to be added. I've tried restarting the router to clear its routing table and the same setup works fine on an old Asus RT-N16 router with Tomato firmware.

Any help is appreciated.

michalis

Forgot to add, the routing table after the VPn connects looks like this:

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
*.*.*.*      *               255.255.255.255 UH    0      0        0 WAN
169.254.0.1     *               255.255.255.255 UH    0      0        0 vlan2
10.0.0.0        *               255.255.255.0   U     0      0        0 LAN
10.10.1.0       *               255.255.255.0   U     0      0        0 tap15
169.254.0.0     *               255.255.0.0     U     0      0        0 vlan2
169.254.0.0     *               255.255.0.0     U     0      0        0 MAN
default         *.*.*.*      0.0.0.0         UG    0      0        0 WAN

The route that is missing I believe is:

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
10.10.1.0       10.10.1.250               255.255.255.0   U     0      0        0 tap15

Traffic

Asus DSL-AC68U does not use OpenVPN.

This is not the Forum you are looking for .. 🙁

michalis

I think it does, under the Vpn section I have two tabs, pptp and openvpn. Also it does connect fine to my openvpn server, it just doesn't add the routes.

I think all Asus routers that are AC* have openvpn.

Traffic

It is not documented in their manual which makes it unsupportable.
https://www.asus.com/Networking/RTAC68U/HelpDesk_Manual/

I suggest you ask Asus why their documentation sucks so bad.

michalis

Sure, Asus may not support it. But it looks like a standard install of OpenVPN, and I have full control of the client config file (I just upload it to the router).
I was hoping someone had a similar issue and could suggest any config changes I could add. I have SSH access to the router so can run any commands via a script.

Traffic

The route is already set:

michalis wrotethe routing table after the VPn connects looks like this:

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
*.*.*.*      *               255.255.255.255 UH    0      0        0 WAN
169.254.0.1     *               255.255.255.255 UH    0      0        0 vlan2
10.0.0.0        *               255.255.255.0   U     0      0        0 LAN
10.10.1.0       *               255.255.255.0   U     0      0        0 tap15

michalis

Yes but that's just the default for the tap device. I think I also need to add an additional route for the gateway 10.10.1.250.