It's been a while since I last posted here, but...
For the love of all things holy, do not try to run your own mailing list server. It will slowly drive you mad with frustration, and is simply not worth it. Email's not what it used to be, and the big providers care deeply about things like DKIM, DMARC, SPF etc, and mailing lists simply do not function properly in this environment. If messages are forwarded without rewriting the signature, they break the signature chain and cause them to be categorised as spam... but if they're forwarded with rewriting the signature, then now the mailing list server is forging messages and trying to send them from a server which isn't authorised by the user's DKIM and they'll be treated as spam. Not to mention that any messages sent from servers on unknown IP addresses will tend to be penalised as spam because they usually are.
It is possible to make this work but it's really brittle and prone to failure. I use gmail, and for the old lua-l I have to disable antispam protection as much as possible, and I still get big banner warnings on every message saying that they look dodgy. These days running a mailing list server which actually works isn't a hobbiest job any more. Just find a big provider and use them. It'll be so much less pain, both for you and your users.
Why, yes, I did use to run one, how can you tell? (I've also written antispam software.)