The Clam Closes

We use a lot of open source software in our team and we try to contribute a little back to the community when we can.  The central mail relay, Oxmail, had been using ClamAV since sometime between 2003 and 2005 … Continue reading

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eduroam and realmless usernames

IT Services’s user-facing instructions for connecting to eduroam have always been unequivocal about the username to use: if you want to connect to eduroam, your username is your SSO with appended on at the end, all lower case. So, … Continue reading

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The University’s mail relays and encryption

By the time this post has been published, the Oxmail relays will most likely be using opportunistic encryption to encrypt outgoing emails, in response to actions by cloud mail providers. However, we would like to make it clear that we … Continue reading

Posted in Mail Relay, Message Submission | Tagged , , | 4 Comments

DNS Resolvers – DNSSEC

We are approaching deployment of a new fleet of DNS resolvers and there are a few questions that we would like feedback from the wider ITSS community. Specifically this post is broaching the subject of DNSSEC. Just to be clear, … Continue reading

Posted in DNS | 6 Comments

FreeRADIUS, sql_log, PostgreSQL and upserting

While this is superficially a post for creating an upsert PostgreSQL query for FreeRADIUS’s sql_log module, I felt the problem was general enough to warrant an explanation as to what CTEs can do. As such, the post should be of … Continue reading

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Linux and eduroam: RADIUS

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: Monitoring

For the past few months my colleague John and I have been trying to explain the inner most details of the new eduroam service, how it’s put together, how it runs and how it’s managed. These posts haven’t shied away … Continue reading

Posted in eduroam, Productivity | 1 Comment

Linux and eduroam: Building for speed and scalability

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

Cisco networking & eduroam: Rate Limiting Using Microflow Policing

This is my final post on the interesting technical aspects of the new networking infrastructure that support the eduroam service around the university. This post covers the finer technical details of how we currently rate limit client devices to 8Mbps … Continue reading

Posted in Cisco Networks, eduroam | 1 Comment

Linux and eduroam: link aggregation with LACP bonding

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