Last updated 4 Jan 2024

Note: List owners have their own FAQ.

If you are looking to mitigate a known CVE vulnerability, please check here.

We've made an attempt here to document a few of the most frequently-asked questions pertaining to running a LISTSERV server. Please take a moment to read through this list and see if your problem is answered here before contacting L-Soft's support hotline.

In general these FAQs apply to both the Classic/Classic HPO and Lite versions of LISTSERV. If there is any question, please consult the Classic/Lite feature comparison chart at

We follow the general convention in this document that references to Internet RFCs (Requests For Comment) such as RFC821 and RFC822 mean "the latest revision of the standard", unless otherwise specifically noted.  Thus, if we mention RFC821, unless we state that we are talking about RFC821 specifically, we mean that you should reference the latest revision, which is currently RFC5321.  Similarly, if we mention RFC822 without saying we mean that specific document, you may reference RFC5322, the current standard.

NOTICE:  If you are experiencing a web interface login problem related to cookies expiring 1/1/2020, please read this FAQ.