This page gives some technical details of the IT Services VPN Service to help in the configuration of firewalls and third-party clients.
VPN clients contact the VPN servers in the netblock 220.127.116.11/28
VPN clients will be given an IP address from the private IP ranges of 10.16.0.0/20 or 10.16.16.0/20. These private addresses will be mapped to a public IP in the 18.104.22.168/22 netblock by the use of dynamic PAT.
The protocols and ports used will depend on whether you are using the older Cisco VPN client, the newer AnyConnect client or a 3rd party or native client.
The Cisco VPN client can operate in one of three transport modes. The client needs access to the following protocols and ports. These details are also relevant to most native clients capable of connecting to the IT Services VPN Service including the OS X native VPN client and clients on iPhone, iPod touch and iPad, as well as many 3rd party clients.
|IPSec||ESP (IP protocol 50), UDP port 500|
|IPSec/TCP||TCP port 10000|
|IPSec/UDP||UDP ports 500, 10000|
The Cisco AnyConnect VPN client requires an SSL tunnel and optionally a DTLS tunnel.
|SSL||TCP port 443|
|DTLS||UDP port 443|
There is nothing that inherently stops clients other than the Cisco VPN client from connecting to the IT Services VPN Service. For example, the open-source vpn client vpnc works well. However, many vendors choose not to support the protocols needed.
The following parameters may help in the configuration of a third-party IPSec client.
|Server platform||Cisco ASA 5500 series|
|Transport mode||IPSec, IPSec/TCP or IPSec/UDP|
|Authentication mode||IKE Extended Authentication (Xauth)|
|IPSec group name||oxford|
|IPSec group password||
|Xauth username||your Remote Access username|
|Xauth password||your Remote Access password|
The following IKE proposals are supported.
|Authentication Algorithm||Encryption Algorithm||Diffie-Hellman Group|
The service does not allow split tunnelling by VPN clients.