Commit | Line | Data |
---|---|---|
431fbb12 | 1 | #! /usr/bin/perl -W |
0bd5c08c | 2 | # |
431fbb12 TH |
3 | # checkmail Version 0.3 by Thomas Hochstein |
4 | # | |
5 | # This script tries to verify the deliverability of (a) mail address(es). | |
6 | # | |
7 | # Copyright (c) 2002-2010 Thomas Hochstein <thh@inter.net> | |
0bd5c08c | 8 | # |
431fbb12 TH |
9 | # It can be redistributed and/or modified under the same terms under |
10 | # which Perl itself is published. | |
11 | ||
12 | our $VERSION = "0.3"; | |
13 | ||
14 | ################################# Configuration ################################ | |
15 | # Please fill in a working configuration! | |
16 | my %config=( | |
17 | # value used for HELO/EHLO - a valid hostname you own | |
18 | helo => 'testhost.domain.example', | |
19 | # value used for MAIL FROM: - a valid address under your control | |
9fc0e927 | 20 | from => 'mailtest@testhost.domain.example' |
431fbb12 TH |
21 | ); |
22 | ||
23 | ################################### Modules #################################### | |
24 | use strict; | |
25 | use File::Basename; | |
0bd5c08c TH |
26 | use Getopt::Std; |
27 | use Net::DNS; | |
28 | use Net::SMTP; | |
29 | ||
431fbb12 TH |
30 | ################################# Main program ################################# |
31 | ||
32 | $Getopt::Std::STANDARD_HELP_VERSION = 1; | |
33 | my $myself = basename($0); | |
34 | ||
35 | # read commandline options | |
0bd5c08c | 36 | my %options; |
431fbb12 TH |
37 | getopts('Vhqlrf:m:', \%options); |
38 | ||
39 | # -V: display version | |
40 | if ($options{'V'}) { | |
41 | print "$myself v $VERSION\nCopyright (c) 2010 Thomas Hochstein <thh\@inter.net>\n"; | |
42 | print "This program is free software; you may redistribute it and/or modify it under the same terms as Perl itself.\n"; | |
43 | exit(100); | |
44 | }; | |
45 | ||
46 | # -h: feed myself to perldoc | |
47 | if ($options{'h'}) { | |
48 | exec('perldoc', $0); | |
49 | exit(100); | |
50 | }; | |
51 | ||
52 | # display usage information if neither -f nor an address are present | |
53 | if (!$options{'f'} and !$ARGV[0]) { | |
54 | print "Usage: $myself [-hqlr] [-m <host>] <address>|-f <file>\n"; | |
55 | print "Options: -V display copyright and version\n"; | |
56 | print " -h show documentation\n"; | |
57 | print " -q quiet (no output, just exit with 0/1/2/3)\n"; | |
58 | print " -l extended logging\n"; | |
59 | print " -r test random address to verify verification\n"; | |
60 | print " -m <host> no DNS lookup, just test this host\n"; | |
61 | print " <address> mail address to check\n\n"; | |
62 | print " -f <file> parse file (one address per line)\n"; | |
63 | exit(100); | |
0bd5c08c TH |
64 | }; |
65 | ||
431fbb12 TH |
66 | # -f: open file and read addresses to @adresses |
67 | my @addresses; | |
0bd5c08c TH |
68 | if ($options{'f'}) { |
69 | if (-e $options{'f'}) { | |
431fbb12 | 70 | open FILE, "<$options{'f'}" or die("$myself ERROR: Could not open file $options{'f'} for reading: $!"); |
0bd5c08c | 71 | } else { |
431fbb12 | 72 | die("$myself ERROR: File $options{'f'} does not exist!\n"); |
0bd5c08c | 73 | }; |
0bd5c08c TH |
74 | while(<FILE>) { |
75 | chomp; | |
431fbb12 | 76 | push(@addresses,$_); |
0bd5c08c TH |
77 | }; |
78 | close FILE; | |
431fbb12 TH |
79 | # fill @adresses with single address to check |
80 | } else { | |
81 | push(@addresses,$ARGV[0]); | |
82 | }; | |
83 | ||
84 | # loop over each address and test it | |
85 | my (%targets,$curstat,$status,$log,$message); | |
86 | foreach (@addresses) { | |
87 | my $address = $_; | |
88 | (undef,my $domain) = splitaddress($address); | |
89 | printf(" * Testing %s ...\n",$address) if !($options{'q'}); | |
90 | $log .= "\n===== BEGIN $address =====\n"; | |
91 | # get list of target hosts or take host forced via -m | |
92 | if (!$options{'m'}) { | |
93 | %targets = %{gettargets($domain,\$log)}; | |
94 | } else { | |
95 | $message = sprintf("Connection to %s forced by -m.\n",$options{'m'}); | |
96 | $log .= $message; | |
97 | print " $message" if !($options{'q'}); | |
98 | # just one target host with preference 0 | |
99 | $targets{$options{'m'}} = 0; | |
100 | }; | |
101 | if (%targets) { | |
102 | $curstat = checkaddress($address,\%targets,\$log); | |
103 | } else { | |
104 | $curstat = 2; | |
105 | $message = 'DNS lookup failure'; | |
106 | printf(" > Address is INVALID (%s).\n",$message) if !($options{'q'}); | |
107 | $log .= $message . '.'; | |
108 | }; | |
109 | $log .= "====== END $address ======\n"; | |
110 | $status = $curstat if (!defined($status) or $curstat > $status); | |
0bd5c08c TH |
111 | }; |
112 | ||
113 | print $log if ($options{'l'}); | |
114 | ||
115 | # status 0: valid / batch processing | |
431fbb12 TH |
116 | # 1: connection failed or temporary failure |
117 | # 2: invalid | |
118 | # 3: cannot verify | |
119 | #D print "\n-> EXIT $status\n"; | |
0bd5c08c TH |
120 | exit($status); |
121 | ||
431fbb12 TH |
122 | ################################## gettargets ################################## |
123 | # get mail exchanger(s) or A record(s) for a domain | |
124 | # IN : $domain: domain to query the DNS for | |
125 | # OUT: \%targets: reference to a hash containing a list of target hosts | |
126 | sub gettargets { | |
127 | my ($domain,$logr) = @_; | |
128 | # resolver objekt | |
129 | my $resolver = Net::DNS::Resolver->new(udp_timeout => 15, tcp_timeout => 15); | |
0bd5c08c | 130 | |
431fbb12 TH |
131 | my %targets; |
132 | # get MX record(s) as a list sorted by preference | |
133 | if (my @mxrr = mx($resolver,$domain)) { | |
134 | print_dns_result($domain,'MX',scalar(@mxrr),undef,$logr); | |
135 | foreach my $rr (@mxrr) { | |
136 | $targets{$rr->exchange} = $rr->preference; | |
137 | $$logr .= sprintf("(%d) %s\n",$rr->preference,$rr->exchange); | |
138 | }; | |
139 | # no MX record found; log and try A record(s) | |
140 | } else { | |
141 | print_dns_result($domain,'MX',undef,$resolver->errorstring,$logr); | |
142 | print(" Falling back to A record ...\n") if !($options{'q'}); | |
143 | # get A record(s) | |
144 | if (my $query = $resolver->query($domain,'A','IN')) { | |
145 | print_dns_result($domain,'A',$query->header->ancount,undef,$logr); | |
146 | foreach my $rr ($query->answer) { | |
147 | $targets{$rr->address} = 0; | |
148 | $$logr .= sprintf("- %s\n",$rr->address); | |
149 | }; | |
150 | # no A record found either; log and fail | |
151 | } else { | |
152 | print_dns_result($domain,'A',undef,$resolver->errorstring,$logr); | |
153 | printf(" %s has neither MX nor A records - mail cannot be delivered.\n",$domain) if !($options{'q'}); | |
154 | }; | |
0bd5c08c | 155 | }; |
431fbb12 TH |
156 | return \%targets; |
157 | }; | |
158 | ||
159 | ################################# checkaddress ################################# | |
160 | # test address for deliverability | |
161 | # IN : $address: adress to be tested | |
162 | # \%targets: reference to a hash containing a list of MX hosts | |
163 | # \$log : reference to the log (to be printed out via -l) | |
164 | # OUT: --- | |
165 | # \$log will be changed | |
166 | sub checkaddress { | |
167 | my ($address,$targetsr,$logr) = @_; | |
168 | my %targets = %{$targetsr}; | |
169 | my $status; | |
170 | # walk %targets in order of preference | |
171 | foreach my $host (sort { $targets{$a} <=> $targets{$b} } keys %targets) { | |
172 | printf(" / Trying %s (%s) with %s\n",$host,$targets{$host} || 'A',$address) if !($options{'q'}); | |
173 | $$logr .= sprintf("%s:\n%s\n",$host,"-" x (length($host)+1)); | |
174 | $status = checksmtp($address,$host,$logr); | |
175 | last if ($status != 1); | |
0bd5c08c | 176 | }; |
431fbb12 | 177 | return $status; |
0bd5c08c TH |
178 | }; |
179 | ||
431fbb12 TH |
180 | ################################### checksmtp ################################## |
181 | # connect to a remote machine on port 25 and test deliverability of a mail | |
182 | # address by doing the SMTP dialog until RCPT TO stage | |
183 | # IN : $address: address to test | |
184 | # $target : target host | |
185 | # \$log : reference to the log (to be printed out via -l) | |
186 | # OUT: .........: reference to a hash containing a list of target hosts | |
187 | # \$log will be changed | |
0bd5c08c | 188 | sub checksmtp { |
431fbb12 TH |
189 | my ($address,$target,$logr) = @_; |
190 | my ($status); | |
191 | # start SMTP connection | |
192 | if (my $smtp = Net::SMTP->new($target,Hello => $config{'helo'},Timeout => 30)) { | |
193 | $$logr .= $smtp->banner; # Net::SMTP doesn't seem to support multiline greetings. | |
194 | $$logr .= "EHLO $config{'helo'}\n"; | |
195 | log_smtp_reply($logr,$smtp->code,$smtp->message); | |
196 | $smtp->mail($config{'from'}); | |
197 | $$logr .= "MAIL FROM:<$config{'from'}>\n"; | |
198 | log_smtp_reply($logr,$smtp->code,$smtp->message); | |
199 | # test address | |
200 | my ($success,$code,@message) = try_rcpt_to(\$smtp,$address,$logr); | |
201 | # connection failure? | |
202 | if ($success < 0) { | |
f18dc26f | 203 | $status = connection_failed(@message); |
431fbb12 TH |
204 | # delivery attempt was successful? |
205 | } elsif ($success) { | |
206 | # -r: try random address (which should be guaranteed to be invalid) | |
207 | if ($options{'r'}) { | |
208 | (undef,my $domain) = splitaddress($address); | |
9fc0e927 | 209 | my ($success,$code,@message) = try_rcpt_to(\$smtp,create_rand_addr($domain),$logr); |
431fbb12 TH |
210 | # connection failure? |
211 | if ($success < 0) { | |
f18dc26f | 212 | $status = connection_failed(@message); |
431fbb12 TH |
213 | # verification impossible? |
214 | } elsif ($success) { | |
215 | $status = 3; | |
216 | print " > Address verificaton impossible. You'll have to send a test mail ...\n" if !($options{'q'}); | |
217 | } | |
218 | } | |
219 | # if -r is not set or status was not set to 3: valid address | |
220 | if (!defined($status)) { | |
221 | $status = 0; | |
222 | print " > Address is valid.\n" if !($options{'q'}); | |
0bd5c08c | 223 | }; |
431fbb12 TH |
224 | # delivery attempt failed? |
225 | } else { | |
226 | $status = 2; | |
227 | print " > Address is INVALID:\n" if !($options{'q'}); | |
228 | print ' ' . join(' ',@message) if !($options{'q'}); | |
229 | } | |
230 | # terminate SMTP connection | |
231 | $smtp->quit; | |
232 | $$logr .= "QUIT\n"; | |
233 | log_smtp_reply($logr,$smtp->code,$smtp->message); | |
0bd5c08c | 234 | } else { |
431fbb12 TH |
235 | # SMTP connection failed / timeout |
236 | $status = connection_failed(); | |
237 | $$logr .= "---Connection failure---\n"; | |
0bd5c08c | 238 | }; |
431fbb12 TH |
239 | return $status; |
240 | } | |
241 | ||
242 | ################################# splitaddress ################################# | |
243 | # split mail address into local and domain part | |
244 | # IN : $address: a mail address | |
245 | # OUT: $local : local part | |
246 | # $domain: domain part | |
247 | sub splitaddress { | |
248 | my($address)=@_; | |
249 | (my $lp = $address) =~ s/^([^@]+)@.*/$1/; | |
250 | (my $domain = $address) =~ s/[^@]+\@(\S*)$/$1/; | |
251 | return ($lp,$domain); | |
252 | }; | |
253 | ||
9fc0e927 TH |
254 | ############################### create_rand_addr ############################### |
255 | # create a random mail address | |
256 | # IN : $domain: the domain part | |
257 | # OUT: $address: the address | |
258 | sub create_rand_addr { | |
259 | my($domain)=@_; | |
260 | my $allowed = 'ABCDEFGHJKLMNPQRSTUVWXYZabcdefghjkmnpqrstuvwxyz23456789-+_='; | |
261 | my $address = ''; | |
262 | while (length($address) < 15) { | |
263 | $address .= substr($allowed, (int(rand(length($allowed)))),1); | |
264 | }; | |
265 | return ($address.'@'.$domain); | |
266 | }; | |
267 | ||
431fbb12 TH |
268 | ################################ parse_dns_reply ############################### |
269 | # parse DNS response codes and return code and description | |
270 | # IN : $response: a DNS response code | |
271 | # OUT: "$response ($desciption)" | |
272 | sub parse_dns_reply { | |
273 | my($response)=@_; | |
274 | my %dnsrespcodes = (NOERROR => 'empty response', | |
275 | NXDOMAIN => 'non-existent domain', | |
276 | SERVFAIL => 'DNS server failure', | |
277 | REFUSED => 'DNS query refused', | |
278 | FORMERR => 'format error', | |
279 | NOTIMP => 'not implemented'); | |
280 | if(defined($dnsrespcodes{$response})) { | |
281 | return sprintf('%s (%s)',$response,$dnsrespcodes{$response}); | |
282 | } else { | |
283 | return $response; | |
284 | }; | |
285 | }; | |
286 | ||
287 | ############################### print_dns_result ############################### | |
288 | # print and log result of DNS query | |
289 | # IN : $domain: domain the DNS was queried for | |
290 | # $type : record type (MX, A, ...) | |
291 | # $count : number of records found | |
292 | # $error : DNS response code | |
293 | # \$log : reference to the log (to be printed out via -l) | |
294 | # OUT: --- | |
295 | # \$log will be changed | |
296 | sub print_dns_result { | |
297 | my ($domain,$type,$count,$error,$logr) = @_; | |
298 | if (defined($count)) { | |
299 | printf(" %d %s record(s) found for %s\n",$count,$type,$domain) if !($options{'q'}); | |
300 | $$logr .= sprintf("%s DNS record(s):\n",$type); | |
301 | } else { | |
302 | printf(" No %s records found for %s: %s\n",$type,$domain,parse_dns_reply($error)) if !($options{'q'}); | |
303 | $$logr .= sprintf("No %s records found: %s\n",$type,parse_dns_reply($error)); | |
304 | }; | |
305 | return; | |
0bd5c08c TH |
306 | }; |
307 | ||
431fbb12 TH |
308 | ################################## try_rcpt_to ################################# |
309 | # send RCPT TO and return replies | |
310 | # IN : \$smtp : a reference to an SMTP object | |
311 | # $recipient: a mail address | |
312 | # \$log : reference to the log (to be printed out via -l) | |
f18dc26f | 313 | # OUT: $success: exit code (0 for false, 1 for true, -1 for tempfail) |
431fbb12 TH |
314 | # $code : SMTP status code |
315 | # $message: SMTP status message | |
316 | # \$log will be changed | |
317 | sub try_rcpt_to { | |
318 | my($smtpr,$recipient,$logr)=@_; | |
319 | $$logr .= sprintf("RCPT TO:<%s>\n",$recipient); | |
f18dc26f TH |
320 | my $success; |
321 | $$smtpr->to($recipient); | |
431fbb12 TH |
322 | if ($$smtpr->code) { |
323 | log_smtp_reply($logr,$$smtpr->code,$$smtpr->message); | |
f18dc26f | 324 | $success = analyze_smtp_reply($$smtpr->code,$$smtpr->message); |
431fbb12 TH |
325 | } else { |
326 | $success = -1; | |
327 | $$logr .= "---Connection failure---\n"; | |
328 | }; | |
329 | return ($success,$$smtpr->code,$$smtpr->message); | |
330 | }; | |
331 | ||
332 | ################################ log_smtp_reply ################################ | |
333 | # log result of SMTP command | |
334 | # IN : \$log : reference to the log (to be printed out via -l) | |
335 | # $code : SMTP status code | |
336 | # @message : SMTP status message | |
337 | # OUT: --- | |
338 | # \$log will be changed | |
339 | sub log_smtp_reply { | |
340 | my($logr,$code,@message)=@_; | |
341 | $$logr .= sprintf('%s %s',$code,join('- ',@message)); | |
342 | return; | |
0bd5c08c TH |
343 | } |
344 | ||
f18dc26f TH |
345 | ############################### analyze_smtp_reply ############################## |
346 | # analyze SMTP response codes and messages | |
347 | # IN : $code : SMTP status code | |
348 | # @message : SMTP status message | |
349 | # OUT: exit code (0 for false, 1 for true, -1 for tempfail) | |
350 | sub analyze_smtp_reply { | |
351 | my($code,@message)=@_; | |
352 | my $type = substr($code, 0, 1); | |
353 | if ($type == 2) { | |
354 | return 1; | |
355 | } elsif ($type == 5) { | |
356 | return 0; | |
357 | } elsif ($type == 4) { | |
358 | return -1; | |
359 | }; | |
360 | return -1; | |
361 | } | |
362 | ||
431fbb12 TH |
363 | ############################## connection_failed ############################### |
364 | # print failure message and return status 1 | |
f18dc26f | 365 | # IN : @message : SMTP status message |
431fbb12 TH |
366 | # OUT: 1 |
367 | sub connection_failed { | |
f18dc26f TH |
368 | my(@message)=@_; |
369 | print " ! Connection failed or other temporary failure.\n" if !($options{'q'}); | |
370 | printf(" %s\n",join(' ',@message)) if @message; | |
431fbb12 TH |
371 | return 1; |
372 | } | |
32301d53 TH |
373 | |
374 | __END__ | |
375 | ||
376 | ################################ Documentation ################################# | |
377 | ||
378 | =head1 NAME | |
379 | ||
380 | checkmail - check deliverability of a mail address | |
381 | ||
382 | =head1 SYNOPSIS | |
383 | ||
384 | B<checkmail> [B<-Vhqlr>] [B<-m> I<host>] I<address>|B<-f> I<file> | |
385 | ||
386 | =head1 REQUIREMENTS | |
387 | ||
388 | =over 2 | |
389 | ||
390 | =item - | |
391 | ||
392 | Perl 5.8 or later | |
393 | ||
394 | =item - | |
395 | ||
396 | File::Basename | |
397 | ||
398 | =item - | |
399 | ||
400 | Getopt::Std | |
401 | ||
402 | =item - | |
403 | ||
404 | Net::DNS I<(CPAN)> | |
405 | ||
406 | =item - | |
407 | ||
408 | Net::SMTP | |
409 | ||
410 | =back | |
411 | ||
412 | Furthermore you'll need a working DNS installation. | |
413 | ||
414 | =head1 DESCRIPTION | |
415 | ||
416 | checkmail checks the vailidity / deliverability of a mail address. | |
417 | You may submit just one address as the last argument or a file | |
418 | containing one address on each line using the B<-f> option. | |
419 | ||
420 | =head2 Configuration | |
421 | ||
422 | For the time being, all configuration is done in the script. You have | |
423 | to set the following elements of the %config hash: | |
424 | ||
425 | =over 4 | |
426 | ||
427 | =item B<$config{'helo'}> | |
428 | ||
429 | The hostname to be used for I<HELO> or I<EHLO> in the SMTP dialog. | |
430 | ||
431 | =item B<$config{'from'}> | |
432 | ||
433 | The sender address to be used for I<MAIL FROM> while testing. | |
434 | ||
32301d53 TH |
435 | =back |
436 | ||
437 | =head2 Usage | |
438 | ||
439 | After configuring the script you may run your first test with | |
440 | ||
441 | checkmail user@example.org | |
442 | ||
443 | B<checkmail> will try to determine the mail exchanger(s) (MX) | |
444 | responsible for I<example.org> by querying the DNS for the respective | |
445 | MX records and then try to connect via SMTP (on port 25) to each of | |
446 | them in order of precedence (if necessary). It will run through the | |
447 | SMTP dialog until just before the I<DATA> stage, i.e. doing I<EHLO>, | |
448 | I<MAIL FROM> and I<RCPT TO>. If no MX is defined, B<checkmail> will | |
449 | fall back to the I<example.org> host itself, provided there is at | |
450 | least one A record defined in the DNS. If there are neither MX nor A | |
451 | records for I<example.org>, mail is not deliverable and B<checkmail> | |
452 | will fail accordingly. If no host can be reached, B<checkmail> will | |
453 | fail, too. Finally B<checkmail> will fail if mail to the given | |
454 | recipient is not accepted by the respective host. | |
455 | ||
456 | If B<checkmail> fails, you'll not be able to deliver mail to that | |
457 | address - at least not using the configured sender address and from | |
458 | the host you're testing from. However, the opposite is not true: a | |
459 | mail you send may still not be delivered even if a test via | |
460 | B<checkmail> succeeds. The receiving entity may reject your mail after | |
461 | the I<DATA> stage, due to content checking or without any special | |
462 | reason, or it may even drop, filter or bounce your mail after finally | |
463 | accepting it. There is no way to be sure a mail will be accepted short | |
464 | of sending a real mail to the address in question. | |
465 | ||
466 | You may, however, try to detect hosts that will happily accept any and | |
467 | all recipient in the SMTP dialog and just reject your mail later on, | |
468 | for example to defeat exactly the kind of check you try to do. | |
469 | B<checkmail> will do that by submitting a recipient address that is | |
470 | known to be invalid; if that address is accepted, too, you'll know | |
471 | that you can't reliably check the validity of any address on that | |
472 | host. You can force that check by using the B<-r> option. | |
473 | ||
474 | If you don't want to see just the results of your test, you can get a | |
475 | B<complete log> of the SMTP dialog by using the B<-l> option. That may be | |
476 | helpful to test for temporary failure conditions. | |
477 | ||
478 | On the other hand you may use the B<-q> option to suppress all output; | |
479 | B<checkmail> will then terminate with one of the following B<exit | |
480 | status>: | |
481 | ||
482 | =over 4 | |
483 | ||
484 | =item B<0> | |
485 | ||
486 | address(es) seem/seems to be valid | |
487 | ||
488 | =item B<1> | |
489 | ||
490 | temporary error (connection failure or temporary failure) | |
491 | ||
492 | =item B<2> | |
493 | ||
494 | address is invalid | |
495 | ||
496 | =item B<3> | |
497 | ||
498 | address cannot reliably be checked (test using B<-r> failed) | |
499 | ||
500 | =back | |
501 | ||
502 | You can do B<batch processing> using B<-f> and submitting a file with | |
503 | one address on each line. In that case the exit status is set to the | |
504 | highest value generated by testing all addresses, i.e. it is set to | |
505 | B<0> if and only if no adress failed, but to B<2> if even one address | |
506 | failed and to B<3> if even one addresses couldn't reliably be checked. | |
507 | ||
508 | And finally you can B<suppress DNS lookups> for MX and A records and | |
509 | just force B<checkmail> to connect to a particular host using the | |
510 | B<-m> option. | |
511 | ||
512 | B<Please note:> You shouldn't try to validate addresses while working | |
513 | from a dial-up or blacklisted host. If in doubt, use the B<-l> option | |
514 | to have a closer look on the SMTP dialog yourself. | |
515 | ||
516 | =head1 OPTIONS | |
517 | ||
518 | =over 3 | |
519 | ||
520 | =item B<-V> (version) | |
521 | ||
522 | Print out version and copyright information on B<checkmail> and exit. | |
523 | ||
524 | =item B<-h> (help) | |
525 | ||
526 | Print this man page and exit. | |
527 | ||
528 | =item B<-q> (quit) | |
529 | ||
530 | Suppress output and just terminate with a specific exit status. | |
531 | ||
532 | =item B<-l> (log) | |
533 | ||
534 | Log and print out the whole SMTP dialog. | |
535 | ||
536 | =item B<-r> (random address) | |
537 | ||
9fc0e927 TH |
538 | Also try a reliably invalid address to catch hosts that try undermine |
539 | address verification. | |
32301d53 TH |
540 | |
541 | =item B<-m> I<host> (MX to use) | |
542 | ||
543 | Force a connection to I<host> to check deliverability to that | |
544 | particular host irrespective of DNS entries. For example: | |
545 | ||
546 | checkmail -m test.host.example user@domain.example | |
547 | ||
548 | =item B<-f> I<file> (file) | |
549 | ||
550 | Process all addresses from I<file> (one on each line). | |
551 | ||
552 | =back | |
553 | ||
554 | =head1 INSTALLATION | |
555 | ||
556 | Just copy checkmail to some directory and get started. | |
557 | ||
558 | You can run your first test with | |
559 | ||
560 | checkmail user@example.org | |
561 | ||
562 | =head1 ENVIRONMENT | |
563 | ||
564 | See documentation of I<Net::DNS::Resolver>. | |
565 | ||
566 | =head1 FILES | |
567 | ||
568 | =over 4 | |
569 | ||
570 | =item F<checkmail.pl> | |
571 | ||
572 | The script itself. | |
573 | ||
574 | =back | |
575 | ||
576 | =head1 BUGS | |
577 | ||
578 | Please report any bugs or feature request to the author or use the | |
579 | bug tracker at L<http://bugs.th-h.de/>! | |
580 | ||
581 | =head1 SEE ALSO | |
582 | ||
583 | L<http://th-h.de/download/scripts.php> will have the current | |
584 | version of this program. | |
585 | ||
586 | This program is maintained using the Git version control system. You | |
587 | may clone L<git://code.th-h.de/mail/checkmail.git> to check out the | |
588 | current development tree or browse it on the web via | |
589 | L<http://code.th-h.de/?p=mail/checkmail.git>. | |
590 | ||
591 | =head1 AUTHOR | |
592 | ||
593 | Thomas Hochstein <thh@inter.net> | |
594 | ||
595 | =head1 COPYRIGHT AND LICENSE | |
596 | ||
597 | Copyright (c) 2002-2010 Thomas Hochstein <thh@inter.net> | |
598 | ||
599 | This program is free software; you may redistribute it and/or modify it | |
600 | under the same terms as Perl itself. | |
601 | ||
602 | =cut |