From: robin_listas@es.invalid   
      
   On 2026-03-05 19:54, Paul wrote:   
   > On Thu, 3/5/2026 3:32 AM, ...w¡ñ§±¤ñ wrote:   
   >> On 3/4/2026 4:18 PM, War Preparations wrote:   
   >>> Can emails be sent within a network without using the internet?   
   >>>   
   >>> For example, governments might block the internet during a war to   
   >>> prevent hackers from spying. If you have your own mail server and only   
   >>> want to communicate with 255 people, would this be possible? Armies   
   >>> around the world would need a way to communicate with their commanders.   
   >>>   
   >>> Just a thought.   
   >>>   
   >>>   
   >>>   
   >>>   
   >>   
   >> A mail server can operate on a local network (LAN) without internet by   
   using internal SMTP/IMAP/POP3 services.   
   >>   
   >> Email clients (Outlook, Thunderbird) need(required) to be configured to   
   point to the local server's IP address for both incoming(POP/IMAP) and   
   outgoing(SMTP).   
   >>   
   >> Email server software is necessary.   
   >>   - open source(free) may be available   
   >>   => when looking for opensource, ensure that the company and development   
   is current. i.e. open source(especially free) may be available, but no longer   
   developed, supported, or updated.   
   >>   
   >>   
   >   
   > I use hmailserver in a VM, to test email clients.   
   >   
   > The hardest part of that, is preparing a certificate for   
   > it to use. The unencrypted options are really disabled   
   > and not usable, leaving only encryption-in-flight and   
   > the email clients expect a valid certificate for that.   
   > And generally, you cannot get a quality certificate   
   > for a mail.local domain . Clients can insist on valid   
   > reverse DNS, and reverse DNS that does not involve   
   > the HOSTS file too.   
   >   
   > It's not trivial removing all the handcuffs on this stuff.   
      
   That's important, because the configuration on a business may use an   
   internal DNS server while Internet is connected, and things get   
   interesting when Internet gets disconnected. Specially with regards to   
   the certificates, which are name based.   
      
   I forgot that I have it working in my LAN without certificates, thus   
   plaintext.   
      
   >   
   > hmailserver is also no longer supported. It was supported   
   > when I first installed it, but it has gone out of support   
   > since.   
   >   
   >     Paul   
      
      
   --   
   Cheers, Carlos.   
   ES🇪🇸, EU🇪🇺;   
      
   --- SoupGate-Win32 v1.05   
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