Texas A&M University - Infrastructure Services

SMTP Relay (smtp-relay.tamu.edu) Configurations

Maximum message size

MaxMessageSize=52428800
This limits the size of messages that the relays will accept to 50MB.

Maximum number of recipients

The relays will accept messages with up to 100 recipients.

SMTP Authentication (SMTP AUTH)

All TAMU users can configure a single out-going SMTP server, regardless of being on- or off-campus or their ISPs SMTP servers by making use of SMTP Authentication (AUTH). The usernames and passwords are your NetIDs and respective passwords. As with all areas where NetID use is possible, the connection MUST be encrypted (the option to use will be listed as "TLS" or "STARTTLS"). If your client supports it, please use the alternate MSA port 587.

  • support AUTH via STARTTLS on port 587
  • support AUTH via SMTPS on port 465
  • support AUTH via STARTTLS on port 25

Reputation Filtering

The SenderBase Reputation Score (SBRS) ranges from -10 to +10.

  • Email from a sender with an SBRS of -3 to -10 will be rejected.
  • Email from a sender with an SBRS greater than -3 but less than or equal to 0 will be throttled.

Other DNS restrictions:

  • Email from a sender with no PTR record will be rejected.
  • Email from a sender with PTR/A record mismatches will be throttled.
  • Email from a sender with more than 15 invalid recipients in an hour will be throttled.

SPF/DKIM

We are not yet publishing SPF or DKIM records, but we are considering them in the SPAM scoring process.

Virus Scanning

  • The relays use Sophos Anti-Virus technology.
  • Incoming or outgoing email that tests positive for a virus is discarded.

Spam Filtering

  • The relays use IronPort's Context Adaptive Scanning Engine (CASE) to score messages.
  • Email with a spam score greater than 90 is discarded.
  • Email with a spam score between 50 and 90 is quarantined.

The spam quarantine is https://devnull.tamu.edu:8443.

  • Digests are sent at 9:00 am and 3:00 pm, Monday through Friday to the message recipient.
  • The digest provides links to the quaratine so that the message recipient can view and/or release messages.
  • Additional options, such as message deletion, sender whitelists, and sender blacklists, are available from the link to view an individual's spam quarantine.
  • Quarantined messages will be held for 30 days defore being deleted.

Overrides to Spam Filtering

An override that cannot be handled by a personal whitelist, such as a SenderBase or DNS override, can be overridden by IP address of the sender's mail server. This whitelists all email from that server and so will be implemented only after due consideration. Email unix-admin@tamu.edu or call Help Desk Central (845-8300) to request a sender override for SenderBase or content rejections.