Radius Authentication to Server Remote from VPN Endpoint

Posted on 2010-11-15
Last Modified: 2013-11-21

I have users who dial-in to an ASA and authenticate via RADIUS to a server at Site A. There is a heavily used site-to-site VPN between site A and Site B. At site B there is another RADIUS server used to authenticate users who dial-in to Site B.

The RADIUS server at site A has gone down so I've added the Site B radius server to the AAA server groups but I'm unable to successfully authenticate across the site-to-site VPN. I've tried adding explicit firewall rules as packet tracer indicates that the failure is due to the implicit ACL but still won't connect.

Any idea how to achieve this?

Question by:TSG_Users
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LVL 29

Expert Comment

by:Alan Huseyin Kayahan
ID: 34193546
What RADIUS is it? Windows IAS?
Can you ping the RADIUS server at site B from ASA command line? Most probably, the interesting traffic does not include the firewall itself.

Author Comment

ID: 34195202

Yes it is IAS and the ACL defines the inside-network/24 to remote-network/24 which includes both the ASA's inside interface address and the remote network entire subnet.

I can't ping the remote server from the ASA, so probably one and the same issue.
LVL 29

Accepted Solution

Alan Huseyin Kayahan earned 500 total points
ID: 34196809
The workaround is typically to issue the command management-access inside at global config, then most probably ping will work (assuming that icmp inspection is in place). If RADIUS still doesnt work although ping works, upgrae your ios to at least 8.0(4), define the RADIUS in asa as following

aaa-server Namehere (inside) host x.x.x.x (IAS server private IP)

Please double-check your port settings etc (1812,1813)
If still doesnt work, then set reverse route injection for the VPN tunnel at both ends, disconnect/reconnect the tunnel and then try again.

If still no joy, I will suggest a different workaround

Author Comment

ID: 34230218
Upgrade of the IOS seemed to fix it, thanks.

Will RRI work on networks where you are not using a routing protocol?
LVL 29

Expert Comment

by:Alan Huseyin Kayahan
ID: 34231996
Reverse route injection is primarily designed for VPN tunnels, so no routing protocol will be required. Routes get installed once the tunnel is up

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