Number of recipients restricted with specific host exceptions

Question

iMS Version: 6.1
I have a need to restrict all senders of email to 10 recipients in a single email message. However, one specific host needs to be able to send to an unlimited (or just a large number) number of recipients on a single message.
From some reading, this isn't all that easy to set up. However, since the exception host is known (by IP/name), we are hoping that simplifies things. Any thoughts?
(the exception host is a server which houses a learning management system. That system allows the professor to send email to the students in the course)

Answer 1

Hi,
Possible to achieve. Requires a few steps though.
1. Isolate off traffic from your LMS system (in this example represented by 1.2.3.4) to a new source channel:
Create a new mapping table in the style of the INTERNAL_IP mapping table (add to the mappings file) e.g. FRIENDLY_IP
FRIENDLY_IP
  $(1.2.3.4/32)  $Y
  *  $NAdd a rewrite rule (imta.cnf) to direct traffic from the FRIENDLY_IP range to the tcp_friendly source channel (needs to be ABOVE the INTERNAL_IP rewrite rule which looks almost the same):
! Do mapping lookup for "friendly", non-internal IP addresses
[] $E$R${FRIENDLY_IP,$L}$U%[$L]@tcp_friendly-daemonCreate a new tcp_friendly channel. This should look the same as your existing tcp_intranet channel e.g.
! tcp_friendly
tcp_friendly smtp mx single_sys subdirs 20 dequeue_removeroute maxjobs 7 pool SMTP_POOL maytlsserver allowswitchchannel saslswitchchannel tcp_auth missingrecipientpolicy 4
tcp_friendly-daemon2. Increase the recipient level on the tcp_friendly channel by adding the "recipientlimit <limit>" keyword e.g.
tcp_friendly smtp mx single_sys subdirs 20 dequeue_removeroute maxjobs 7 pool SMTP_POOL maytlsserver allowswitchchannel saslswitchchannel tcp_auth missingrecipientpolicy 4 recipientlimit 1003. Lock down the recipient limit for other traffic.
Edit the channel definitions for other source channels (such as tcp_local/tcp_intranet/tcp_submit/tcp_auth) and add a smaller recipient (recipientlimit 10) e.g.
tcp_intranet smtp mx single_sys subdirs 20 dequeue_removeroute maxjobs 7 pool SMTP_POOL maytlsserver allowswitchchannel saslswitchchann
el tcp_auth missingrecipientpolicy 4 recipientlimit 10Then run ./imsimta cnbuild ; ./imsimta restart for it to take effect. You should see emails from your LMS system coming from tcp_friendly rather then tcp_local/tcp_intranet.
Recommend you run through and test these steps on a development/test system first of course.
Regards,
Shane.