3030 SMTP Service Extensions for Transmission of Large and Binary MIME
2920 SMTP Service Extension for Command Pipelining. N. Freed.
2852 Deliver By SMTP Service Extension. D. Newman. June 2000. (Format:
2554 SMTP Service Extension for Authentication. J. Myers. March 1999.
2487 SMTP Service Extension for Secure SMTP over TLS. P. Hoffman.
2034 SMTP Service Extension for Returning Enhanced Error Codes. N.
1891 SMTP Service Extension for Delivery Status Notifications. K.
1846 SMTP 521 Reply Code. A. Durand, F. Dupont. September 1995.
1870 SMTP Service Extension for Message Size Declaration. J. Klensin,
1428 Transition of Internet Mail from Just-Send-8 to 8bit-SMTP/MIME.
1652 SMTP Service Extension for 8bit-MIMEtransport. J. Klensin, N.
