<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <title>Poptop MSCHAP2 ADS Howto</title> </head> <body> <p><strong>15. Freeradius</strong></p> <p>Firstly, for Fedora 8, add user radiusd to group wbpriv.</p> <blockquote> <pre>[root@pptp ~]# usermod -G wbpriv radiusd</pre> </blockquote> <p>For Fedora 4 / 5 / 6, change the permission of the winbind_privileged directory. </p> <blockquote> <pre>[root@pptp ~]# chgrp radiusd /var/cache/samba/winbindd_privileged/</pre> </blockquote> <p>Secondly, we will need to modify the freeradius configuration file. Fortunately, we have only to change a few lines. </p> <hr> <a name="mschap2"></a><strong>15.1 Configure Freeradius for MSCHAPv2 </strong> <p>Edit /etc/raddb/radiusd.conf to enable MSCAHP2. Open the file and locate the module section and then the mschap subsection.</p> <blockquote> <pre>modules {<br> ....[snip]....<br> mschap { use_mppe = yes require_encryption = yes require_strong = yes ntlm_auth = "/usr/bin/ntlm_auth --request-nt-key --username=%{Stripped-User-Name:-%{User-Name:-None}} --challenge=%{mschap:Challenge:-00} --nt-response=%{mschap:NT-Response:-00}"<br> }<br> ....[snip]....<br> } </pre> </blockquote> <p>The mschap option in the authorize and authenticate sections is enabled by default. If they are not, enable them accordingly. Save the file. </p> <p>The radius server has a secret key for security. The default key for freeradius is testing123. It is a good idea to change it for obvious security reasons. The key is in /etc/raddb/clients.conf. </p> <blockquote> <pre>client 127.0.0.1 {<br> #<br> # The shared secret use to "encrypt" and "sign" packets between<br> # the NAS and FreeRADIUS. You MUST change this secret from the<br> # default, otherwise it's not a secret any more!<br> #<br> # The secret can be any string, up to 32 characters in length.<br> #<br> secret = testing123 ....[snip].... </pre> </blockquote> <p><strong>Note</strong>: if you change the secret key, you must modify the /etc/radiusclient-ng/servers so that they match each other. </p> <p>Refer to <a href="poptop_ads_howto_a6.htm">Appendix 6</a> for information on Fedora 4 / 5 / 6.</p> <hr> <p><strong><a name="access"></a>15.2 PPTP Access Control </strong></p> <p>The above configuration allows everyone with a valid userID in the AD to connect to the pptpd server. If you want to restrict access to a group of users, you can create a group, say VPN_Allowed, in the AD. Add users to the group and modify the ntml_auth line in /etc/raddb/radius.conf to include the parameter "--require-membership-of=EXAMPLE+VPN_Allowed". </p> <p>In the example, I split the line into multiple lines for clarity. It should be one continuous line in the configuration file. </p> <blockquote> <pre>ntlm_auth = "/usr/bin/ntlm_auth --request-nt-key --username=%{Stripped-User-Name:-%{User-Name:-None}} --challenge=%{mschap:Challenge:-00} --nt-response=%{mschap:NT-Response:-00} --require-membership-of=EXAMPLE+VPN_Allowed"</pre> </blockquote><p></p> <hr> <a href="poptop_ads_howto_10.htm">Next</a> <a href="poptop_ads_howto_8.htm">Previous</a> <a href="poptop_ads_howto_1.htm#toc">Content</a><p> </p> </body> </html>