Re:Could this be FUD? (Score 1)

No its not. This is very true and happening a LOT. I run Sendmail ( a mail server, also known as MTA) on a fairly busy mail service and have ended up using Barracuda Spam Control - https://login.barracudanetwork... to manage the insane amount of spam and virus attacks (PDF files) that I recieved just in the last few years. We had upwards of 400,000 emails an hour full of PDF laden viruses just last week...

This is a real time graphs of attacks and mails to our Barracuda Gateway to give you an idea:

** You can see countries from where attacks are coming and a little snapshot of mail volume **.

http://prntscr.com/cmc1wx

When the mail does hit our MTA, running sendmail; we run it through SA -- which also updates itself automatically (via cron) **sa-update **.

Some imporant notes:

1) You DO need clamav or else spam will the last of your worries....(Also note that clamav is a memory beast). You can also use Symatec but I have completely moved from them to ESET (Desktop) and ClamAV + Barracuda for rest.

2) RBLS: we use these:

FEATURE(dnsbl,`blackholes.mail-abuse.org', ` Mail from $&{client_addr} rejected; see http://mail-abuse.org/cgi-bin/... {client_addr}')dnl FEATURE(dnsbl,`dialups.mail-abuse.org', ` Mail from dial-up rejected; see http://mail-abuse.org/dul/endu... FEATURE(dnsbl,`zen.spamhaus.org', ` Mail from zen rejected; see https://www.spamhaus.org/zen/'...

3) Also note, that we dont listen on IPv6 even though we serve content on http. The reason (as being discussed in postfix-users (a mailing list for one the more popular mail servers) is exactly this problem. The increase of IoT devices and proliferation of IPv6 makes is next to impossible to now scan from IPv6 hosts. So as such, we dont. Although Google, Microsoft internall uses IPv6 to route emails.

4) I do not work for Barracuda.

5) Dyn's transactional email delivery option is really good. And so is Office 365 relay via their MTA (which also adds dkim signatures) and mostly would mean your mail would be delivered.

Please leave a message here if you want me to look at it.