OpenVPN Slow Speeds DD-WRT

klop2031

Background:

I have an OpenVPN server running on my Netgear R7000 [openddwrt] router. My ISP connection is 50 mb/s down and 12 mb/s up (although it is up to 25 mb/s). When connecting to my vpn from my cellphone, and windows computer I never get any higher than 3-5 mb/s down, and sometimes I can get 3-4 mp/s up. I tested the speed on my phone I get over 8 mb/s down. The CPU is averaging at 4-10%. I have checked top while running a speed test and I am getting 2% load.

What I have tried:

Changing from AES-256-CBC to BF-CBC
Removing compression
Setting it to UDP
Setting the sndbuf 0 and rcvbuf 0
Changing MTU-TUN to 1500

Question: All changes have done nothing to the speed. Is there anything I can do to improve my speed?

Server Config: (This was pulled from /tmp/openvpn/openvpn.conf in dd-wrt)

dh /tmp/openvpn/dh.pem
ca /tmp/openvpn/ca.crt
cert /tmp/openvpn/cert.pem
key /tmp/openvpn/key.pem
keepalive 10 120
verb 3
mute 3
syslog
writepid /var/run/openvpnd.pid
management 127.0.0.1 14
management-log-cache 100
topology subnet
script-security 2
port 8005
proto udp
cipher aes-128-cbc
auth sha1
client-connect /tmp/openvpn/clcon.sh
client-disconnect /tmp/openvpn/cldiscon.sh
client-config-dir /tmp/openvpn/ccd
tls-server
ifconfig-pool-persist /tmp/openvpn/ip-pool 86400
client-to-client
fast-io
tun-mtu 1500
mtu-disc yes
server-bridge 192.168.1.1 255.255.255.0 192.168.1.50 192.168.1.55
dev tap2
tls-auth /tmp/openvpn/ta.key 0
#Route internet^M
push "route 192.168.0.0 255.255.255.0"^M
push "dhcp-option DNS 192.168.1.1"^M
push "redirect-gateway def1"^M
push "route-gateway 192.168.1.1"^M
sndbuf 393216^M
rcvbuf 393216^M
push "sndbuf 393216"^M
push "rcvbuf 393216"^M
keepalive 10 60^M
verb 5

Client Config:

client
#dev tun
dev tap
proto udp
remote Remote.Server 8005
resolv-retry infinite
nobind
persist-key
persist-tun
tls-auth ta.key 1

ca ca.crt
cert laptopPass.crt
key laptopPass.key

redirect-gateway def1
remote-cert-tls server
cipher AES-128-CBC
sndbuf 0
rcvbuf 0
#link-mtu 6089
tun-mtu 1500
auth-nocache
#comp-lzo
verb 4

Firewall

iptables -I INPUT 1 -p udp –-dport 8005 -j ACCEPT
iptables -I FORWARD 1 –-source 192.168.1.0/24 -j ACCEPT

Any ideas as to what I may be doing wrong? Anything I can look at to troubleshoot?

Traffic

One thing you can address:

NOTE: your local LAN uses the extremely common subnet address 192.168.0.x or 192.168.1.x. Be aware that this might create routing conflicts if you connect to the VPN server from public locations such as internet cafes that use the same subnet.

:arrow: Never use 192.168.0.0/24 or 192.168.1.0/24 (or other common subnets) for your OpenVPN Server LAN :!:

You are advised to change your server LAN to a more unique RFC1918 compliant subnet. f.e 192.168.143.0/24

klop2031

Should I change these lines to this:

server-bridge 192.168.143.1 255.255.255.0 192.168.143.50 192.168.1.55
#Route internet^M
push "route 192.168.143.0 255.255.255.0"^M
push "dhcp-option DNS 192.168.143.1"^M
push "redirect-gateway def1"^M
push "route-gateway 192.168.143.1"^M

mccloud

The thing that's terribly bottlenecking my VPN speeds on my DD-WRT router is the hardware itself... check the specs on yours. Perhaps it's just not able to perform the required operations at a sufficient rate.