Pretty much every popular provider blocks port 25 out by default, and they'll instead try to steer customers to use a smart host. However, some, including Linode, will unblock port 25 by request: https://www.linode.com/docs/guides/running-a-mail-server/#sending-email-on-linode

On Tue, Sep 26, 2023 at 6:11 AM Daniel Corbe <daniel@corbe.net> wrote:
Hey all,

I apologize if this isn't the right place to post this; however, I
thought maybe the NANOG community would be able to point me in the right
direction.

I'm looking for a place that I can host a mailer.  My primary use case
is a Mailman-style technical discussion list; much like NANOG but
software related instead of network related: READ: non-commercial in nature.

I'm currently a vultr customer, but they're refusing to unblock port 25
on my account.  I've tried explaining my use case but no matter who I
talk to over there they just keep pointing me to their spam policy.

Thanks!
-Daniel


--
Jonathan Leist
Staff Engineer