Mailman problems

For one of lists, one of the sub­scri­bers had the stran­gest pro­blem. He kept get­ting boun­ces that the list ali­as does not even exist, whilst at the same time other sub­scri­bers could well wri­te to that list. It turns out that his mail ser­ver was rewri­ting the To:-address, resol­ving the CNAME of the host­na­me that is respon­si­ble for run­ning the lists. As we run a vir­tu­al-domain based mail ser­ver, this was not a smart choice: Whilst the email address does inde­ed exist on the CNAME‑d host (lists.xiqit.de), it does not exist on the ful­ly qua­li­fied name the ser­ver lis­tens to. So we added an MX record for the host­na­me that also points to the ‚pri­ma­ry‘ name of the ser­ver (the one which the RDNS also resol­ves to), and now all is well. HIs email does reach the list.