You can see some documentation on DD-WRT at http://www.dd-wrt.com/wiki/index.php/OpenVPN

Settings

Server: The gateway you want to use, such as 'dfw2.gpvpn.com' port: 8888
tunnel: tun
tunnel protocol: udp
enc cypher: AES-256-CBC
hash algo: SHA1
cert verification: checked

Advanced Options: Enable

TLS Cipher – None
LZO Compression – Disabled
NAT – Enable
Firewall – Disable (Incoming ports are blocked by NAT firewall)
Tunnel MTU – 1500

Insert into Additional Config:

keepalive 10 120
remote-cert-tls server
redirect-gateway

CA Cert:
-----BEGIN CERTIFICATE----- MIIDQDCCAqmgAwIBAgIJAM8Brk2pUr0KMA0GCSqGSIb3DQEBBQUAMHQxCzAJBgNV BAYTAlVTMQswCQYDVQQIEwJDQTEMMAoGA1UEBxMDVlBOMQwwCgYDVQQKEwNWUE4x DDAKBgNVBAsTA1ZQTjEMMAoGA1UEAxMDVlBOMQwwCgYDVQQpEwNWUE4xEjAQBgkq hkiG9w0BCQEWA1ZQTjAeFw0xMjAzMDMwMjExNDJaFw0yMjAzMDEwMjExNDJaMHQx CzAJBgNVBAYTAlVTMQswCQYDVQQIEwJDQTEMMAoGA1UEBxMDVlBOMQwwCgYDVQQK EwNWUE4xDDAKBgNVBAsTA1ZQTjEMMAoGA1UEAxMDVlBOMQwwCgYDVQQpEwNWUE4x EjAQBgkqhkiG9w0BCQEWA1ZQTjCBnzANBgkqhkiG9w0BAQEFAAOBjQAwgYkCgYEA wY2K08N7or1Br/EsD9XBon7gs7dKflWYuymgMLJfeMFWuJloNdsn+3GARIhYBbN6 zhvFGFE214qKPqAydW1WmIIK7KoC0sgndr+Vk/au9gssFzVmmvr6+WN/nfo2L9Kv vBMoYLrMAiyw/D4cRapZi2pXJLcMDfC+p1VWAX8TYWkCAwEAAaOB2TCB1jAdBgNV HQ4EFgQUmyvO4rTnu5/ABnp0FngU+SdR8WAwgaYGA1UdIwSBnjCBm4AUmyvO4rTn u5/ABnp0FngU+SdR8WCheKR2MHQxCzAJBgNVBAYTAlVTMQswCQYDVQQIEwJDQTEM MAoGA1UEBxMDVlBOMQwwCgYDVQQKEwNWUE4xDDAKBgNVBAsTA1ZQTjEMMAoGA1UE AxMDVlBOMQwwCgYDVQQpEwNWUE4xEjAQBgkqhkiG9w0BCQEWA1ZQToIJAM8Brk2p Ur0KMAwGA1UdEwQFMAMBAf8wDQYJKoZIhvcNAQEFBQADgYEAoB0kOuGvrzPBTIRX IDHCCxBMdny+3sKAOllmH4+51j2aWhAJ4Pyc/yBTYyQGNoriABjmNzp+R05oiaxA D3vTgR80juKDPtQb8LoGLBF18gL7Vtc3+hJXcJasXZaDSSoyh5f+TtGvytIT+ece JWIrKnFXzlHOvKlyLkcZn15gwKQ=
-----END CERTIFICATE-----

Public Client Cert:
-----BEGIN CERTIFICATE----- MIIDizCCAvSgAwIBAgIBAjANBgkqhkiG9w0BAQUFADB0MQswCQYDVQQGEwJVUzEL MAkGA1UECBMCQ0ExDDAKBgNVBAcTA1ZQTjEMMAoGA1UEChMDVlBOMQwwCgYDVQQL EwNWUE4xDDAKBgNVBAMTA1ZQTjEMMAoGA1UEKRMDVlBOMRIwEAYJKoZIhvcNAQkB FgNWUE4wHhcNMTIwMzAzMDIxMjU3WhcNMjIwMzAxMDIxMjU3WjB3MQswCQYDVQQG EwJVUzELMAkGA1UECBMCQ0ExDDAKBgNVBAcTA1ZQTjEMMAoGA1UEChMDVlBOMQww CgYDVQQLEwNWUE4xDzANBgNVBAMTBmNsaWVudDEMMAoGA1UEKRMDVlBOMRIwEAYJ KoZIhvcNAQkBFgNWUE4wgZ8wDQYJKoZIhvcNAQEBBQADgY0AMIGJAoGBAMqp/gXr FASElUb7kFDInvlb6ZT8Vfm1QdiBD3AfvzqVisV9cPDue/mvDyn1JYOHrswUrkmS YATBsV3eDyJfc77TYiKqn0afCtSK7CeJ0syDwm9cCRqjbQV7NjF3hSgUg0JSHFOl TQMxo8DFunEAzSjUhgVIZQyPSQYCe8tcNcKpAgMBAAGjggEoMIIBJDAJBgNVHRME AjAAMC0GCWCGSAGG+EIBDQQgFh5FYXN5LVJTQSBHZW5lcmF0ZWQgQ2VydGlmaWNh dGUwHQYDVR0OBBYEFOdEvdvwdzDQnrhX5q1cyfoXB/tgMIGmBgNVHSMEgZ4wgZuA FJsrzuK057ufwAZ6dBZ4FPknUfFgoXikdjB0MQswCQYDVQQGEwJVUzELMAkGA1UE CBMCQ0ExDDAKBgNVBAcTA1ZQTjEMMAoGA1UEChMDVlBOMQwwCgYDVQQLEwNWUE4x DDAKBgNVBAMTA1ZQTjEMMAoGA1UEKRMDVlBOMRIwEAYJKoZIhvcNAQkBFgNWUE6C CQDPAa5NqVK9CjATBgNVHSUEDDAKBggrBgEFBQcDAjALBgNVHQ8EBAMCB4AwDQYJ KoZIhvcNAQEFBQADgYEAmI8mqE20A2xJmCthBHUMdj39qUpXBhRk7XZQ1YyBXCAn gt/a0sfjMIGQJsDFNh4sCplN0mHBGqX74G3sSiTa07mhGNhqg196LKfbBchNn2Nn HaCqjO0NG9Q2c/0tt47DyOfo7QOTcRzApO3W6SOcPCBLaRihohUmnv1i2kGhJbw= -----END CERTIFICATE-----

Private Client Key:
-----BEGIN PRIVATE KEY----- MIICeAIBADANBgkqhkiG9w0BAQEFAASCAmIwggJeAgEAAoGBAMqp/gXrFASElUb7 kFDInvlb6ZT8Vfm1QdiBD3AfvzqVisV9cPDue/mvDyn1JYOHrswUrkmSYATBsV3e DyJfc77TYiKqn0afCtSK7CeJ0syDwm9cCRqjbQV7NjF3hSgUg0JSHFOlTQMxo8DF unEAzSjUhgVIZQyPSQYCe8tcNcKpAgMBAAECgYEAsHf5M1oQ4iY4fciLT2yB0QvR huN6UacdINKwiKd8Mh0I6xJhh8mBtlZS0+wcsD0zXY0cff+xEDNAqEW10+5dr11Y zYpViacZRMQnrzBEYcTSqlfHXg2PZxu4c08ndwDxjm03Vgg5RKvQnGRMRy4lH/HP OiAkb9oJgR0R5sccZgECQQDmfVZF2UBn4u2scjfcPl4XsUrPO8eyie995c7s7Cz1 TDiecLCesjLRf97RexfhhwNJurfCZUWNJ9hkq5hUGzvJAkEA4Rg/ziL74sBh+jT6 2TaAqnmHDWZlrfCfKtlm1z4TQ5E6WpjKNXN3qfKW069QGnRjZn8zuPwgMpBPXeaT jHH/4QJBAJslbvchX7sOA1H6qCM2T/u+uU55PNivBGhIUlskNrb/EXWFAT4xUQe3 /PIg21hRmyL77kmKBaEYWw6YerbShhECQQCX2Rb6BamszyGJfAIZVGY6Gp+bz48a Zy/I5T42R/8Q3sDh6x7GLi30rN1I0oSURB3mQDtxOEy0L5wK+Yhh/2mhAkAGXya9 wUOcSz96jUgnMfiVoBT3BNszzn/HLKCipCPd/eR3FEvpfmNN+olkd09cONMDKCcW CfHad9moALon0bIV
-----END PRIVATE KEY-----