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

The University’s mail relays and encryption

Posted on 2016-02-17 by Christopher Causer

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

I just received a spam email from my own address

Posted on 2013-03-08 by Guy Edwards

Our team was asked to answer some queries about how it’s possible to receive mail that has been forged as being from your email address. This article slightly overlaps with a previous article in 2011 that covered similar ground. Please note … Continue reading →

Posted in Mail Relay | Comments Off on I just received a spam email from my own address

Joe Job Spam Run

Posted on 2011-05-03 by Guy Edwards

The university received two spam run campaigns, the first uses a forged sender to make a university address look like the sender, the second uses forged university addresses (i.e. not accounts) in an outgoing campaign to other sites, resulting in … Continue reading →

Posted in Mail Relay | 2 Comments

AOL mail

Posted on 2010-12-21 by Guy Edwards

Just a minor post about an issue some people might have seen (things are fairly quiet in the runup to Christmas). If you had an issue delivering mail to or from an aol.com address today this post explains why. I … Continue reading →

Posted in Mail Relay | Comments Off on AOL mail

Cisco firewall SMTP “fixup” considered harmful

Posted on 2009-11-26 by Oliver Gorwits

This issue is old and familiar to us, and crops up about once every six months or so. I thought it might help to document the situation more publicly. On Cisco firewalls (PIX or the newer ASA), various protocol inspection … Continue reading →

Posted in Cisco Networks, Firewall, Mail Relay, Message Submission | 9 Comments

URIBL is back

Posted on 2009-09-02 by Andy Saunders

We had to remove Oxmail’s checking of URIs against the URIBL blacklist a couple of weeks ago after a change of licensing meant that we could no longer use it for free. JANET(UK) has now purchased a private datafeed and … Continue reading →

Posted in Mail Relay | Comments Off on URIBL is back