| 1 | .TH dot-qmail 5 |
| 2 | .SH NAME |
| 3 | dot-qmail \- control the delivery of mail messages |
| 4 | .SH DESCRIPTION |
| 5 | Normally the |
| 6 | .B qmail-local |
| 7 | program delivers each incoming message to your system mailbox, |
| 8 | .IR homedir\fB/Mailbox , |
| 9 | where |
| 10 | .I homedir |
| 11 | is your home directory. |
| 12 | |
| 13 | It can instead |
| 14 | write the mail to a different file or directory, |
| 15 | forward it to another address, |
| 16 | distribute it to a mailing list, |
| 17 | or even execute programs, |
| 18 | all under your control. |
| 19 | .SH "THE QMAIL FILE" |
| 20 | To change |
| 21 | .BR qmail-local 's |
| 22 | behavior, set up a |
| 23 | .B .qmail |
| 24 | file in your home directory. |
| 25 | |
| 26 | .B .qmail |
| 27 | contains one or more lines. |
| 28 | Each line is a delivery instruction. |
| 29 | .B qmail-local |
| 30 | follows each instruction in turn. |
| 31 | There are five types of delivery instructions: |
| 32 | (1) comment; (2) program; (3) forward; (4) mbox; (5) maildir. |
| 33 | .TP 5 |
| 34 | (1) |
| 35 | A comment line begins with a number sign: |
| 36 | |
| 37 | .EX |
| 38 | # this is a comment |
| 39 | .EE |
| 40 | |
| 41 | .B qmail-local |
| 42 | ignores the line. However, |
| 43 | .BR qmail-valid-addresses (8) |
| 44 | interprets some markers in comments. If the first line of a |
| 45 | .B .qmail |
| 46 | file begins `#!' then the address (or addresses) controlled by the file |
| 47 | are considered invalid, and any attempt to send to them is refused by |
| 48 | .BR qmail-smtpd (8). |
| 49 | (Note: This doesn't prevent local users sending mail directly. This |
| 50 | feature can therefore be used to experiment with mail rules before |
| 51 | allowing the entire Internet to break them.) If the first line of a |
| 52 | .B .qmail |
| 53 | file begins `#?' then |
| 54 | .BR qmail-smtpd (8) |
| 55 | will consult a Userv service |
| 56 | .BI addrcheck: ext |
| 57 | to decide whether addresses matched by the extension |
| 58 | .I ext |
| 59 | are valid. The service is passed many arguments, though the first two |
| 60 | are the most interesting. The first is the local-part tail (i.e., the |
| 61 | bit that matched |
| 62 | .BR default ) |
| 63 | and the second is the envelope sender. |
| 64 | .TP 5 |
| 65 | (2) |
| 66 | A program line begins with a vertical bar: |
| 67 | |
| 68 | .EX |
| 69 | |preline /usr/ucb/vacation djb |
| 70 | .EE |
| 71 | |
| 72 | .B qmail-local |
| 73 | takes the rest of the line as a command to supply to |
| 74 | .BR sh . |
| 75 | See |
| 76 | .B qmail-command(8) |
| 77 | for further information. |
| 78 | .TP 5 |
| 79 | (3) |
| 80 | A forward line begins with an ampersand: |
| 81 | |
| 82 | .EX |
| 83 | &me@new.job.com |
| 84 | .EE |
| 85 | |
| 86 | .B qmail-local |
| 87 | takes the rest of the line as a mail address; |
| 88 | it uses |
| 89 | .B qmail-queue |
| 90 | to forward the message to that address. |
| 91 | The address must contain a fully qualified domain name; |
| 92 | it must not contain extra spaces, angle brackets, or comments: |
| 93 | |
| 94 | .EX |
| 95 | # the following examples are WRONG |
| 96 | .br |
| 97 | &me@new |
| 98 | .br |
| 99 | &<me@new.job.com> |
| 100 | .br |
| 101 | & me@new.job.com |
| 102 | .br |
| 103 | &me@new.job.com (New Address) |
| 104 | .EE |
| 105 | |
| 106 | If the address begins with a letter or number, |
| 107 | you may leave out the ampersand: |
| 108 | |
| 109 | .EX |
| 110 | me@new.job.com |
| 111 | .EE |
| 112 | |
| 113 | Note that |
| 114 | .B qmail-local |
| 115 | omits its new |
| 116 | .B Return-Path |
| 117 | line when forwarding messages. |
| 118 | .TP 5 |
| 119 | (4) |
| 120 | An |
| 121 | .I mbox |
| 122 | line begins with a slash or dot, |
| 123 | and does not end with a slash: |
| 124 | |
| 125 | .EX |
| 126 | /home/djb/Mailbox.sos |
| 127 | .EE |
| 128 | |
| 129 | .B qmail-local |
| 130 | takes the entire line as a filename. |
| 131 | It appends the mail message to that file, |
| 132 | using |
| 133 | .BR flock -style |
| 134 | file locking if possible. |
| 135 | .B qmail-local |
| 136 | stores the mail message in |
| 137 | .I mbox |
| 138 | format, as described in |
| 139 | .BR mbox(5) . |
| 140 | |
| 141 | .B WARNING: |
| 142 | On many systems, |
| 143 | anyone who can read a file can |
| 144 | .B flock |
| 145 | it, and thus hold up |
| 146 | .BR qmail-local 's |
| 147 | delivery forever. |
| 148 | Do not deliver mail to a publicly accessible file! |
| 149 | |
| 150 | If |
| 151 | .B qmail-local |
| 152 | is able to lock the file, but has trouble writing to it |
| 153 | (because, for example, the disk is full), |
| 154 | it will truncate the file back to its original length. |
| 155 | However, it cannot prevent mailbox corruption if the system |
| 156 | crashes during delivery. |
| 157 | .TP 5 |
| 158 | (5) |
| 159 | A |
| 160 | .I maildir |
| 161 | line begins with a slash or dot, |
| 162 | and ends with a slash: |
| 163 | |
| 164 | .EX |
| 165 | /home/djb/Maildir/ |
| 166 | .EE |
| 167 | |
| 168 | .B qmail-local |
| 169 | takes the entire line as the name of a directory in |
| 170 | .I maildir |
| 171 | format. |
| 172 | It reliably stores the incoming message in that directory. |
| 173 | See |
| 174 | .B maildir(5) |
| 175 | for more details. |
| 176 | .TP 5 |
| 177 | (6) |
| 178 | An |
| 179 | .I sender |
| 180 | line begins with a less-than-sign `<'. The remainder of the line is set |
| 181 | as the new envelope sender for any forwarding done through this file. |
| 182 | .TP 5 |
| 183 | (7) |
| 184 | An |
| 185 | .I environment |
| 186 | line begins with an exclamation mark `!'. If the remainder of the line |
| 187 | has the form |
| 188 | .IB var = value |
| 189 | then the environment variable |
| 190 | .I var |
| 191 | is set to |
| 192 | .I value |
| 193 | for the following program deliveries. If there is no equals sign, the |
| 194 | named environment variable is deleted. |
| 195 | .PP |
| 196 | If |
| 197 | .B .qmail |
| 198 | has the execute bit set, |
| 199 | it must not contain any |
| 200 | program lines, |
| 201 | .I mbox |
| 202 | lines, |
| 203 | or |
| 204 | .I maildir |
| 205 | lines. |
| 206 | If |
| 207 | .B qmail-local |
| 208 | sees any such lines, |
| 209 | it will stop and indicate a temporary failure. |
| 210 | |
| 211 | If |
| 212 | .B .qmail |
| 213 | is completely empty (0 bytes long), or does not exist, |
| 214 | .B qmail-local |
| 215 | follows the |
| 216 | .I defaultdelivery |
| 217 | instructions set by your system administrator; |
| 218 | normally |
| 219 | .I defaultdelivery |
| 220 | is |
| 221 | .BR ./Mailbox , |
| 222 | so |
| 223 | .B qmail-local |
| 224 | appends the mail message to |
| 225 | .B Mailbox |
| 226 | in |
| 227 | .I mbox |
| 228 | format. |
| 229 | |
| 230 | .B .qmail |
| 231 | may contain extra spaces and tabs at the end of a line. |
| 232 | Blank lines are allowed, but not for the first line of |
| 233 | .BR .qmail . |
| 234 | |
| 235 | If |
| 236 | .B .qmail |
| 237 | is world-writable or group-writable, |
| 238 | .B qmail-local |
| 239 | stops and indicates a temporary failure. |
| 240 | .SH "SAFE QMAIL EDITING" |
| 241 | Incoming messages can arrive at any moment. |
| 242 | If you want to safely edit your |
| 243 | .B .qmail |
| 244 | file, first set the sticky bit on your home directory: |
| 245 | |
| 246 | .EX |
| 247 | chmod +t $HOME |
| 248 | .EE |
| 249 | |
| 250 | .B qmail-local |
| 251 | will temporarily defer delivery of any message to you |
| 252 | if your home directory is sticky |
| 253 | (or group-writable or other-writable, |
| 254 | which should never happen). |
| 255 | Make sure to |
| 256 | |
| 257 | .EX |
| 258 | chmod -t $HOME |
| 259 | .EE |
| 260 | |
| 261 | when you are done! |
| 262 | It's a good idea to test your new |
| 263 | .B .qmail |
| 264 | file as follows: |
| 265 | |
| 266 | .EX |
| 267 | qmail-local -n $USER ~ $USER '' '' '' '' ./Mailbox |
| 268 | .EE |
| 269 | .SH "EXTENSION ADDRESSES" |
| 270 | In the |
| 271 | .B qmail |
| 272 | system, |
| 273 | you control all local addresses of the form |
| 274 | .IR user\fBBREAK\fIanything , |
| 275 | as well as the address |
| 276 | .I user |
| 277 | itself, |
| 278 | where |
| 279 | .I user |
| 280 | is your account name. |
| 281 | Delivery to |
| 282 | .I user\fBBREAK\fIanything |
| 283 | is controlled by the file |
| 284 | .IR homedir/\fB.qmail\-\fIanything . |
| 285 | (These rules may be changed by the system administrator; |
| 286 | see |
| 287 | .BR qmail-users (5).) |
| 288 | |
| 289 | The |
| 290 | .B alias |
| 291 | user controls all other addresses. |
| 292 | Delivery to |
| 293 | .I local |
| 294 | is controlled by the file |
| 295 | .IR homedir/\fB.qmail\-\fIlocal , |
| 296 | where |
| 297 | .I homedir |
| 298 | is |
| 299 | .BR alias 's |
| 300 | home directory. |
| 301 | |
| 302 | In the following description, |
| 303 | .B qmail-local |
| 304 | is handling a message addressed to |
| 305 | .IR local@domain , |
| 306 | where |
| 307 | .I local |
| 308 | is controlled by |
| 309 | .BR .qmail\-\fIext . |
| 310 | Here is what it does. |
| 311 | |
| 312 | If |
| 313 | .B .qmail\-\fIext |
| 314 | is completely empty, |
| 315 | .B qmail-local |
| 316 | follows the |
| 317 | .I defaultdelivery |
| 318 | instructions set by your system administrator. |
| 319 | |
| 320 | If |
| 321 | .B .qmail\-\fIext |
| 322 | doesn't exist, |
| 323 | .B qmail-local |
| 324 | will try some default |
| 325 | .B .qmail |
| 326 | files. |
| 327 | For example, |
| 328 | if |
| 329 | .I ext |
| 330 | is |
| 331 | .BR foo-bar , |
| 332 | .B qmail-local |
| 333 | will try first |
| 334 | .BR .qmail-foo-bar , |
| 335 | then |
| 336 | .BR .qmail-foo-default , |
| 337 | and finally |
| 338 | .BR .qmail-default . |
| 339 | If none of these exist, |
| 340 | .B qmail-local |
| 341 | will bounce the message. |
| 342 | (Exception: for the basic |
| 343 | .I user |
| 344 | address, |
| 345 | .B qmail-local |
| 346 | treats a nonexistent |
| 347 | .B .qmail |
| 348 | the same as an empty |
| 349 | .BR .qmail .) |
| 350 | |
| 351 | .B WARNING: |
| 352 | For security, |
| 353 | .B qmail-local |
| 354 | replaces any dots in |
| 355 | .I ext |
| 356 | with colons before checking |
| 357 | .BR .qmail\-\fIext . |
| 358 | For convenience, |
| 359 | .B qmail-local |
| 360 | converts any uppercase letters in |
| 361 | .I ext |
| 362 | to lowercase. |
| 363 | |
| 364 | When |
| 365 | .B qmail-local |
| 366 | forwards a message as instructed in |
| 367 | .B .qmail\-\fIext |
| 368 | (or |
| 369 | .BR .qmail-default ), |
| 370 | it checks whether |
| 371 | .B .qmail\-\fIext\fB-owner\fP |
| 372 | exists. |
| 373 | If so, |
| 374 | it uses |
| 375 | .I local\fB-owner@\fIdomain |
| 376 | as the envelope sender for the forwarded message. |
| 377 | Otherwise it retains the envelope sender of the original message. |
| 378 | Exception: |
| 379 | .B qmail-local |
| 380 | always retains the original envelope sender |
| 381 | if it is the empty address or |
| 382 | .BR #@[] , |
| 383 | i.e., if this is a bounce message. |
| 384 | |
| 385 | .B qmail-local |
| 386 | also supports |
| 387 | .B variable envelope return paths |
| 388 | (VERPs): |
| 389 | if |
| 390 | .B .qmail\-\fIext\fB-owner\fP |
| 391 | and |
| 392 | .B .qmail\-\fIext\fB-owner-default\fP |
| 393 | both exist, it uses |
| 394 | .I local\fB\-owner\-@\fIdomain\fB-@[] |
| 395 | as the envelope sender. |
| 396 | This will cause a recipient |
| 397 | .I recip\fB@\fIreciphost |
| 398 | to see an envelope sender of |
| 399 | .IR local\fB\-owner\-\fIrecip\fB=\fIreciphost\fB@\fIdomain . |
| 400 | .SH "ERROR HANDLING" |
| 401 | If a delivery instruction fails, |
| 402 | .B qmail-local |
| 403 | stops immediately and reports failure. |
| 404 | .B qmail-local |
| 405 | handles forwarding after all other instructions, |
| 406 | so any error in another type of delivery will prevent all forwarding. |
| 407 | |
| 408 | If a program returns exit code 99, |
| 409 | .B qmail-local |
| 410 | ignores all succeeding lines in |
| 411 | .BR .qmail , |
| 412 | but it still pays attention to previous forward lines. |
| 413 | |
| 414 | To set up independent instructions, |
| 415 | where a temporary or permanent failure in one instruction |
| 416 | does not affect the others, |
| 417 | move each instruction into a separate |
| 418 | .B .qmail\-\fIext |
| 419 | file, and set up a central |
| 420 | .B .qmail |
| 421 | file that forwards to all of the |
| 422 | .BR .qmail\-\fIext s. |
| 423 | Note that |
| 424 | .B qmail-local |
| 425 | can handle any number of forward lines simultaneously. |
| 426 | .SH "SEE ALSO" |
| 427 | envelopes(5), |
| 428 | maildir(5), |
| 429 | mbox(5), |
| 430 | qmail-users(5), |
| 431 | qmail-local(8), |
| 432 | qmail-command(8), |
| 433 | qmail-queue(8), |
| 434 | qmail-lspawn(8) |