This limits the size of messages that the relays will accept to 50MB.
The relays will accept messages with up to 100 recipients.
The Proofpoint appliances used for smtp-relay.tamu.edu do regular garbage collection on the anti-spam/anti-virus processes. When a node is doing housekeeping, SMTP is still running, but because the anti-spam/anti-virus processes are not available, the SMTP service responds with SMTP "421 4.7.0" I'm busy, try again later messages. Many applications and appliances do not handle an SMTP 4xx gracefully and most end up losing the message.
While the neo.tamu.edu mail servers lived on campus, it was common for these applications and appliances to hand off messages to those servers. As part of decommissioning of the neo.tamu.edu email complex, relay.tamu.edu was set up for use by applications and devices to hand off email without having to meet the formal correctness requirements of the actual, internet-facing relays.
If you have devices that need to email but have problems talking to smtp-relay.tamu.edu, please point them to relay.tamu.edu port 25.
All Texas A&M NetID account holders can configure a single out-going SMTP server using SMTP Authentication (AUTH), regardless of being on- or off-campus or their Internet Service Providers SMTP servers. The username and password for AUTH are a user's NetID and respective password. 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 mail submission (MSA) port 587.
Available SMTP AUTH ports on smtp-relay.tamu.edu are:
We are not yet publishing SPF or DKIM records, but we are considering them in the SPAM scoring process.
The spam quarantine is https://devnull.tamu.edu.
An override that cannot be handled by a personal safe-list, such as a PDR or MLX override, can be overridden by Texas A&M IT. This safe-lists all email from that server and so will be implemented only after due consideration. Email email@example.com or call Help Desk Central (979.845.8300) to request administrative intervention.