On Mi, 20 oct 21, 19:14:20, deloptes wrote: > Martin McCormick wrote: > > > The installation, here, is like millions of others. We are on a > > private VLAN with the router acting as the gateway to our ISP's > > network and the internet. There is nothing unusual about that so > > the question is Can systems on a 192.168.x VLAN use smtp to send > > mail to each other? > > > > I think you are using the term VLAN improperly. FRom what I know VLAN is > virtual LAN, which is usually achieved with tagging. Technically most routers are actually using VLANs to distinguish between WAN and LAN, but this is indeed irrelevant in this case.
> But the answer to your question is yes they can. > > > I really should know the answer to this because I am a > > retired systems engineer who used unix systems and mailers all > > the time but that was in a university network and I would just > > assign a DNS name to each box and maybe a MX record if it was > > necessary so that box1.midlevel.edu could deliver mail to > > box2.midlevel.edu whether it was across the room or on another > > continent. > > > > And for the 192.168.0.0/16 apply same rules ... well you can also > use /etc/hosts. > > > The DNS support is what you don't have on a private VLAN > > so I want to do this in a safe but simple way. > > > > You do not have, because you did not install and configure, but from my > experience if you manage more devices, you should consider using DHCP and > MTA > > There are all sort of solutions like minimal DNS etc. IMO DHCP is must + > DNS, minimal DNS or /etc/hosts file In case you already own a public domain name you might be tempted to use that also internally. It's probably better to use a domain name that only exists on your LAN instead (e.g. use the domain name without the TLD), to avoid any issues in case a misconfigured system tries to send e-mail outside your LAN. > > This would make it possible for Linux boxes on the > > network to send messages to the system I normally receive mail on > > so that squawks about a process crashing or some other problem > > are sure to be seen. > > > > good conclusion - go for that > > > The other systems sending those messages don't even > > necessarily need to send mail outside the network but they do > > need to send mail to the system I normally read mail on. > > > > I would consider something as server, because if your machine is not > reachable, you will have the complains in the log files and bouncing mail. > > So basically you need the whole concept. IMAP or POP/MTA/DHCP/DNS Unless local mail is always read on the "server" system. > > I looked up this topic using duckduckgo and found very > > little hits that were on topic and lots of mercantile buzz about > > email hosting companies, etc. All are necessary but not what I > > was asking about. > > > > I have put static IP records in to the dhcp server on our > > router so 192.168.1.xx will always either have a specific host at > > that address or nothing if the MAC address changes and the record > > hasn't been updated. > > > > Also, I have put /etc/hosts files on Linux systems and a > > Mac and I believe there is a hosts file one can add to Windows > > systems for a similar effect. > > if you implement DHCP and DNS in the router make sure you make backup of the > configuration. you are left with the MTA and IMAP/POP In addition to all the above, you will need a minimal MTA on the machines only sending e-mail, e.g. something like nullmailer or esmtp. dma stands out here because it has a sort of queue and can also deliver locally if needed. For the "server" machine you will a real SMTP server. Typical choices are Exim (Debian's default) and Postfix (used by e.g. lists.debian.org), though they might be slightly difficult to configure. Another less known alternative is OpenSMTPD, which is lightweight enough to use also on the send-only systems. Hope this helps, Andrei -- http://wiki.debian.org/FAQsFromDebianUser
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