March 17, 2023, 4:50pm
I can certainly agree with the frustrations of sending email
however over the last few years I’ve had very few problems sending email through my server.
I just happened to produce a video the other day and took some notes:
MXtoolbox.com for testing domains. green icons are great anything other is not. On Virtualmin I find managing these settings very easy.
I also have a lot of settings in Postfix, for example things like this "reject_unauth_pipelining reject_non_fqdn_recipient "
thats not my complete setup.
DMARC and Reverse DNS are extremly important in my opinion.
I ran a check on 12 mail servers the other day and at least 10 of them had issues.
March 17, 2023, 4:56pm
also if you are using your own PHP script to send what is the format of the send message.
for example, the headers are important, who its from and ties in with the sending mail. also setting a valid and good constructed Message-Id is important now (I only included this in lasy year or two)
March 17, 2023, 5:00pm
sorry for multiple posts
also I check the incoming URL for hackers and spammers. as soon as I see something along these lines I ban their IP address, so they only get one chance (per IP address)
Unless you wanna spend all day checking logs you need a automatic system as the hackers/bots do not stop.
March 17, 2023, 9:40pm
yes, its an automatic system. there are quite a few checks on my list.
yes I can tell how frequent they try.
so far so good keeping them at bay, but its constant so need to regulary check the logs for new tricks
the only important think that it complains is about rDNS but that’s setup for my second IP, unfortunately though, being a single Postfix instance using same HELO for both IPs with both having the same rDNS, the name can only be resolved back to one of the IPs so maybe this is again a flag for some providers
Can you sort this out by using a single FQDN for all of your hosted domain’s MX?
March 19, 2023, 8:24am
yes, thats what I do. use the single FQDN as the mail server name for all the hosted domains on that server. means I get a valid Reverse DNS response