qmail-smtpd.8 (3987B)
1 .TH qmail-smtpd 8 2 .SH NAME 3 qmail-smtpd \- receive mail via SMTP 4 .SH SYNOPSIS 5 .B qmail-smtpd 6 .SH DESCRIPTION 7 .B qmail-smtpd 8 receives mail messages via the Simple Mail Transfer Protocol (SMTP) 9 and invokes 10 .B qmail-queue 11 to deposit them into the outgoing queue. 12 .B qmail-smtpd 13 must be supplied several environment variables; 14 see 15 .BR tcp-environ(5) . 16 17 .B qmail-smtpd 18 is responsible for counting hops. 19 It rejects any message with 100 or more 20 .B Received 21 or 22 .B Delivered-To 23 header fields. 24 25 .B qmail-smtpd 26 supports ESMTP, including the 8BITMIME and PIPELINING options. 27 .SH TRANSPARENCY 28 .B qmail-smtpd 29 converts the SMTP newline convention into the UNIX newline convention 30 by converting CR LF into LF. 31 It returns a temporary error and drops the connection on bare LFs; 32 see 33 .BR https://cr.yp.to/docs/smtplf.html . 34 35 .B qmail-smtpd 36 accepts messages that contain long lines or non-ASCII characters, 37 even though such messages violate the SMTP protocol. 38 .SH "CONTROL FILES" 39 .TP 5 40 .I badmailfrom 41 Unacceptable envelope sender addresses. 42 .B qmail-smtpd 43 will reject every recipient address for a message 44 if the envelope sender address is listed in 45 .IR badmailfrom . 46 A line in 47 .I badmailfrom 48 may be of the form 49 .BR @\fIhost , 50 meaning every address at 51 .IR host . 52 .TP 5 53 .I databytes 54 Maximum number of bytes allowed in a message, 55 or 0 for no limit. 56 Default: 0. 57 If a message exceeds this limit, 58 .B qmail-smtpd 59 returns a permanent error code to the client; 60 in contrast, if 61 the disk is full or 62 .B qmail-smtpd 63 hits a resource limit, 64 .B qmail-smtpd 65 returns a temporary error code. 66 67 .I databytes 68 counts bytes as stored on disk, not as transmitted through the network. 69 It does not count the 70 .B qmail-smtpd 71 Received line, the 72 .B qmail-queue 73 Received line, or the envelope. 74 75 If the environment variable 76 .B DATABYTES 77 is set, it overrides 78 .IR databytes . 79 80 .TP 5 81 .I dnsbllist 82 A list of dnsbl providers that 83 .B qmail-smtpd 84 checks to identify blacklisted ip addresses. 85 86 Exception: 87 If the environment variable 88 .B DNSBLSKIP 89 is set, 90 .B qmail-smtpd 91 ignores 92 .IR dnsbllist , 93 and the dnsbl check is not performed. 94 The check is skipped even if some other authentication method succedeed 95 and authorized the client to relay (smtp-auth or tls client certificate), 96 or if 97 .B RELAYCLIENT 98 enviromnent variable is set. 99 100 .TP 5 101 .I localiphost 102 Replacement host name for local IP addresses. 103 Default: 104 .IR me , 105 if that is supplied. 106 .B qmail-smtpd 107 is responsible for recognizing dotted-decimal addresses for the 108 current host. 109 When it sees a recipient address of the form 110 .IR box@[d.d.d.d] , 111 where 112 .I d.d.d.d 113 is a local IP address, 114 it replaces 115 .IR [d.d.d.d] 116 with 117 .IR localiphost . 118 This is done before 119 .IR rcpthosts . 120 .TP 5 121 .I morercpthosts 122 Extra allowed RCPT domains. 123 If 124 .I rcpthosts 125 and 126 .I morercpthosts 127 both exist, 128 .I morercpthosts 129 is effectively appended to 130 .IR rcpthosts . 131 132 You must run 133 .B qmail-newmrh 134 whenever 135 .I morercpthosts 136 changes. 137 138 Rule of thumb for large sites: 139 Put your 50 most commonly used domains into 140 .IR rcpthosts , 141 and the rest into 142 .IR morercpthosts . 143 .TP 5 144 .I rcpthosts 145 Allowed RCPT domains. 146 If 147 .I rcpthosts 148 is supplied, 149 .B qmail-smtpd 150 will reject 151 any envelope recipient address with a domain not listed in 152 .IR rcpthosts . 153 154 Exception: 155 If the environment variable 156 .B RELAYCLIENT 157 is set, 158 .B qmail-smtpd 159 will ignore 160 .IR rcpthosts , 161 and will append the value of 162 .B RELAYCLIENT 163 to each incoming recipient address. 164 165 .I rcpthosts 166 may include wildcards: 167 168 .EX 169 heaven.af.mil 170 .heaven.af.mil 171 .EE 172 173 Envelope recipient addresses without @ signs are 174 always allowed through. 175 .TP 5 176 .I smtpgreeting 177 SMTP greeting message. 178 Default: 179 .IR me , 180 if that is supplied; 181 otherwise 182 .B qmail-smtpd 183 will refuse to run. 184 The first word of 185 .I smtpgreeting 186 should be the current host's name. 187 .TP 5 188 .I timeoutsmtpd 189 Number of seconds 190 .B qmail-smtpd 191 will wait for each new buffer of data from the remote SMTP client. 192 Default: 1200. 193 .SH "SEE ALSO" 194 tcp-env(1), 195 tcp-environ(5), 196 qmail-control(5), 197 qmail-inject(8), 198 qmail-newmrh(8), 199 qmail-queue(8), 200 qmail-remote(8)