Agent forwarding is a special case of remote tunneling. In agent forwarding, Secure Shell connections and public-key authentication data are forwarded from one server to another without the user having to authenticate separately for each server. Authentication data does not have to be stored on any other machine than the local host, and authentication passphrases or private keys never go over the network. For more information, see Forwarding User Authentication.

SSH Tectia Client and ConnectSecure provide authentication agent functionality and the Connection Broker can also serve OpenSSH clients as an authentication agent. SSH Tectia Server supports agent forwarding on Unix platforms. Thus, the start and end points of the agent forwarding chain can be Windows or Unix hosts, but all hosts in the middle of the forwarding chain must be Unix hosts and must have both the Secure Shell client and server components installed.

It is also possible to forward the certificate authentication data to obtain Kerberos ticket from a third host and continue authenticating to further hosts with the GSSAPI/Kerberos method.

Figure 8.7. Agent forwarding

By default, SSH Tectia Server allows agent forwarding for all users. To enable agent forwarding only for the specified users, include an entry similar to the following in your ssh-server-config.xml file:

<services>
  <rule group="admins">
    <tunnel-agent action="allow" />
    ...
  </rule>
  <rule>
    <tunnel-agent action="deny" />
  </rule>
</services>