SMTP Relay Service Description

Overview

The CNS Open Systems Group maintains the campus-wide open-access Simple Mail Transfer Protocol (SMTP) server. This service is commonly referred to as the outgoing mail server.

SMTP is used by Mail User Agents (MUA) to send messages, and by Mail Transport Agents (MTA) to deliver messages to their destinations.

Restrictions

Sending messages to non ufl.edu recipients is called relaying. In order to relay messages, one of the following must be true:

You authenticate to smtp.ufl.edu with your Gatorlink username and password.
You are logged into the campus Virtual private Network (VPN).
The computer you are using must be on a managed network. That is, a network maintained by CNS Network Services, or by a University department.

Dialup lines, walkup ports, and wireless conections are considered unmanaged, and require the authentication mentioned above.

Size

Email larger than 20MB will be rejected by the smtp server. Email is a very poor method to send data files because of the special encoding required to transmit the data in email form. A file sent through email will be aproximatly 33% larger than if sent with conventional methods.

Attachments

To avoid the spread of email borne computer maladies attachments with the following extensions will be blocked:

ade, adp, app, asd, asf, asx, bas, bat, chm, cmd, com, cpl, crt, dll, exe, fxp, hlp, hta, hto, inf, ini, ins, isp, jse?, lib, lnk, mdb, mde, msc, msi, msp, mst, ocx, pcd, pif, prg, reg, scr, sct, sh, shb, shs, sys, url, vb, vbe, vbs, vcs, vxd, wmd, wms, wmz, wsc, wsf, wsh

Relevent Internet RFCs

Following are the RFCs with which this service complies:

RFC ID	Topic
RFC974	MX routing
RFC976	UUCP mail format
RFC1123	Host requirements (modifies 821, 822, and 974)
RFC1344	Implications of MIME for Internet Mail Gateways
RFC1652	SMTP Service Extension for 8bit-MIMEtransport
RFC1869	SMTP Service Extensions (ESMTP spec)
RFC1870	SMTP Service Extension for Message Size Declaration
RFC1892	Multipart/Report Content Type for the Reporting of Mail System Administrative Messages
RFC1893	Enhanced Mail System Status Codes
RFC1894	An Extensible Message Format for Delivery Status Notifications
RFC1985	SMTP Service Extension for Remote Message Queue Starting
RFC2033	Local Mail Transfer Protocol (LMTP)
RFC2034	SMTP Service Extension for Returning Enhanced Error Codes
RFC2045	Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies
RFC2487	SMTP Service Extension for Secure SMTP over TLS
RFC2821	Simple Mail Transfer Protocol
RFC2822	Internet Message Format
RFC2920	SMTP Service Extension for Command Pipelining

Data Classifications

Sendmail Configuration Files

Description: These files control the operation of the Sendmail software. This class includes all databases and maps directly used by the service that are not otherwise classified.
Data Principal: Stephen Ulmer
Data Custodian: OSG Staff
Data User: Automated Systems
Data Confidentiality: Low
Data Integrity: Low
Data Availability: High

Sendmail Authinfo Map

Description: This map contains credentials allowing Sendmail to authenticate to the Cyrus LMTP daemons to deliver mail messages.
Data Principal: Stephen Ulmer
Data Custodian: OSG Staff
Data User: Automated Systems
Data Confidentiality: High
Data Integrity: Low
Data Availability: High

Mail Messages

We consider the messages themselves to be severally owned by the message sender and each message recipient. The data security and availability implications of each individual message are the responsibility of its owners. OSG does not further classify this data.