| < Free Open Study > |
|
qmail includes the following Simple Mail Transfer Protocol (SMTP) service features:
RFC compliant. Complies with RFC 2821 (SMTP), RFC 1123, RFC 1651 (ESMTP), RFC 1652 (8-bit MIME), and RFC 1854 (pipelining).
8-bit clean. Accepts 7-bit ASCII characters as well as 8-bit extended characters.
Supports IDENT (RFC 931/1413/TAP) callback. This allows cooperating mail administrators to determine the identity of users abusing the system.
Relay control. qmail automatically denies unauthorized relaying by outsiders.
Automatic recognition of local Internet Protocol (IP) addresses. Messages to jessica@[192.168.1.3] are recognized as local by qmail-smtpd if 192.168.1.3 is a local IP address.
Per-buffer timeouts. Each new buffer of data from the remote SMTP client has its own time limit.
Hop counting for detection of looping messages. Messages that pass through more than 100 delivery hops are rejected.
Parallelism limit. Using tcpserver, which is part of the ucspi-tcp package, the number of concurrent incoming SMTP sessions can be controlled.
Refusal of connections from known abusers. Using tcpserver, specific hosts and domains can be refused access to the SMTP server.
Relaying and message rewriting for authorized clients. The RELAYCLIENT environment variable can be used to allow authorized hosts to relay or to modify header fields for specified hosts.
Optional RBL support. Using rblsmtpd, from the ucspi-tcp package, access can be denied to known senders of junk e-mail—also known as spam.
| < Free Open Study > |
|