Email: Sympa Confirmation emails being rejected because of DKIM

Posted on 2026-05-01 by Christopher Causer

This blog post springs out of some debugging we in Networks Development and Support have been doing to understand why some Sympa email is being rejected by Hotmail, due to a DKIM failure. To get there, it may be good … Continue reading →

Posted in Linux, Mail Relay | Tagged | 2 Comments

Linux and eduroam: RADIUS

Posted on 2015-02-16 by Christopher Causer

A service separate from, but tightly coupled to, eduroam is our RADIUS service. This is the service that authenticates a user, making sure that the username and password typed into the password dialog box (or WPA supplicant) is correct. Authorization … Continue reading →

Posted in eduroam, Linux | Tagged , , , | 3 Comments

Linux and eduroam: Building for speed and scalability

Posted on 2014-08-21 by Christopher Causer

When upgrading the eduroam infrastructure, there was one goal in mind: increase the bandwidth over the previous one. The old infrastructure made use of a Linux box to perform NAT, netflow and firewalling duties. This can all be achieved with … Continue reading →

Posted in eduroam, Firewall, Linux | Tagged , | 3 Comments

Linux and eduroam: link aggregation with LACP bonding

Posted on 2014-07-31 by Christopher Causer

In previous posts, I discussed the roles of routing and NATing in the new eduroam infrastructure . In one sense, that is all you need to create a Linux NAT firewall. However, the setup is not very resilient. The resulting … Continue reading →

Posted in eduroam, Linux | Tagged , , , | 8 Comments

Linux’s role in the new eduroam infrastructure

Posted on 2014-06-05 by Christopher Causer

People within Oxford University may be aware that the eduroam service has recently been upgraded to increase its bandwidth, which was saturated on the old infrastructure. This included the replacement of two Linux servers which provide services key to the … Continue reading →

Posted in eduroam, Linux | Tagged , | Comments Off on Linux’s role in the new eduroam infrastructure