OpenVPN connection OK with Win client but very slow with Mac client (Tunnelblick)
Posted on 2009-07-14
I have OpenVPN 2.1 installed on a Linux server (CentOS 5.3) and different users connect to it through Windows client GUI. The connection has been working great if the Windows client is used.
However, when the OpenVPN client is Tunnelblick on a Mac (OS X Leopard 18.104.22.168), the connection is problematic. It establishes just fine but the ping gets very slow once you start transferring more data. In other words, if you run the ping command in terminal, it looks OK but if you then for example open an URL, it becomes extremely slow, the ping can suddenly change from 30ms to 2000ms and then comes back to 30ms once there is no data transfer again.
Any idea why this is happening? There does not seem to be any error recorded in the server logs.
Here is the server configuration:
auth-user-pass-verify "/etc/openvpn/vpnauth.php" via-file
tls-auth /etc/openvpn/keys/ta.key 0
server 10.88.12.0 255.255.254.0
push "redirect-gateway def1"
push "dhcp-option DNS 10.88.12.1"
management 127.0.0.1 4445
keepalive 10 120
Here is the client configuration:
tls-auth keys/ta.key 1
Again, this server+client configuration is working great as long the client is Windows OpenVPN. I have tried TCP configuration with a few modifications (different port etc.) but the problem persisted.
Any idea where there is the problem on Macs? Tunnelblick is the newest version available and so is the server (2.1.x OpenVPN branch).