$mailprog = '/usr/lib/sendmail -i -t';
This variable must define the location to your server's sendmail program. If this is incorrect, form results will not be mailed to you. Specifying the parameters in this variable is new in v1.91, and we have included the -i parameter so that a single period on a line by itself will not end the message. -t instructs sendmail to read the recipient list from the message text.

@referers = ('scriptarchive.com','YOUR_IP');
This array allows you to define the domains on which you allow forms to reside and use this installation of FormMail. If a user tries to put a form on another server, that is not scriptarchive.com, they will receive an error message when someone tries to fill out their form. By placing scriptarchive.com in the @referers array, this also allows www.scriptarchive.com, ftp.scriptarchive.com, any other http address with scriptarchive.com in it and scriptarchive.com's IP address to access this script as well, so no users will be turned away.
NOTE: This is not a security check. Referer headers can EASILY be faked. Rather, it prevents someone on xyznotyou.com from using the FormMail on your server to process forms on their server on a regular basis. It remains in the script as a remnant of earlier versions when it was used for security, but the @recipients variable is now used to specify exactly who can receive e-mail from this installation.

As of version 1.7, the domains listed here are also used as the defaults when checking valid recipient e-mail addresses. You should either include all domain names that you wish to have FormMail send e-mails to in your @referers array or tailor the @recipients array by hand.


@valid_ENV = ('REMOTE_HOST','REMOTE_ADDR','REMOTE_USER', 'HTTP_USER_AGENT');
This array allows the administrator to specify a list of environment variables that the user may request be added into the e-mail. This is a security patch that was advised at http://www.securityfocus.com/bid/1187 and was implemented by Peter D. Thompson Yezek at http://www.securityfocus.com/archive/1/62033.
Only environment variables listed in this array may be included in the form field env_report. So if you wanted to also know what URL a user was submitting from, you could change @valid_ENV to:

@valid_ENV = ('REMOTE_HOST','REMOTE_ADDR','REMOTE_USER',
'HTTP_USER_AGENT','HTTP_REFERER');

and then include HTTP_REFERER in your env_report form field.


@recipients = &fill_recipients(@referers);
If you wish to only allow e-mail addresses at the domain names in @referers to receive form results, you probably do not need to change this variable. However, if you get any 'Error: Bad/No Recipient' messages when running FormMail, you may have to revisit @recipients and make sure you have correctly listed all domains or configured this variable.
@recipients is the most important variable you need to configure. It is an array of regular expressions defining all valid recipients that can be specified. In order for an e-mail to be sent to the recipient defined in a form, the recipient e-mail address must match one of the elements in the @recipients array.

SIMPLE SETUP:

For the most simple setup, place any domain name that you wish to send form results to in the @referers array. Warning: This allows those domains to also access your FormMail script and utilize it to process their own forms, but likely this is what you intended anyway. If so, you can leave:

@recipients = &fill_recipients(@referers);
NO, THAT IS NOT WHAT I INTENDED!
Another alternative, then, is to set @recipients equal to the return value of the fill-recipients function and pass this function all of the domains to which e-mail may be addressed:

@recipients = &fill_recipients('domain.com',
'sub.domain.com','another.com');
You are now allowing e-mail to any username (provided it contains only A-Z, a-z, 0-9, _, - or .) at those three domains.
Similarly, since @recipients is just an array, you could even do:

@recipients = (&fill_recipients('domain.com','sub.domain.com'),
'^otheruser1@otherhost\.com',
'^otheruser2@otherhost\.com');
This would allow any recipient at domain.com and sub.domain.com similar to the previous example, but would also allow your friends otheruser1 and otheruser2 on otherhost.com to use your FormMail! Of course, you will need to add otherhost.com into your @referers array if a form is on their host!
HOW DOES THAT WORK?

When the fill_recipients function is called on an array of domain names, it turns them into regular expressions. These regular expressions will only allow e-mail messages to go to a recipient with an e-mail address in the following format:

[A-Za-z0-9_-\.]+@domain.com

where domain.com is specified in @referers. For any IP addresses in @referers, the following address formats are valid:

[A-Za-z0-9_-\.]+@[192.168.1.1]

where 192.168.1.1 is the specified IP address in @referers.

What this means in english is that the only valid addresses are those to usernames that include only letters, numbers, underscores, dashes or periods and an exact domain name or IP address that was specified in the @referers array. Depending on your needs, this may be too broad or not broad enough.

WHAT IF YOU NEED MORE FLEXIBILITY??

The way FormMail validates a recipient address is to check the supplied recipient(s) in the submitted form against each element in the array @recipients (which is a list of Perl regular expressions). If any valid recipients are found, they will receive a copy of the message.

Using the examples of @referers = ('domain.com','192.168.1.1'); and the default usage of setting @recipients = &fill_recipients(@referers), the contents of @recipients are now the same as if you had written:

@recipients = ('^[\w\-\.]+\@domain\.com',
'^[\w\-\.]+\@\[192\.168\.1\.1\]');
What these regular expressions instruct FormMail to do is require that any e-mail address passed in as a recipient of the form submission match at least one of those two formats. The following are examples of valid and invalid recipients for this exact setup:
VALID:

user@domain.com, First.Last@domain.com,
Last-First@domain.com, user_name@domain.com,
user023@domain.com, user@[192.168.1.1],
First.Last@[192.168.1.1], user023@[192.168.1.1],
Last-First@[192.168.1.1], user_name@[192.168.1.1], etc.
INVALID: (using these in your form field 'recipient' will trigger error)
user%name@domain.com, user(name)@domain.com,
first:last@domain.com ,
domain.com, user@192.168.1.1,
user@newdomain.com, user@sub.domain.com,
user@domainname.com
Essentially, it only allows A-Z, a-z, 0-9, _, - and . in the local address area (before the @, represented as [\w\-\.]+ in regular expression speak) and requires the domain name to match exactly. When mailing to an IP address, it must be enclosed in [].
BUT I NEED TO MATCH MORE CHARACTERS IN THE USERNAME!

Let's say you need to be able to deliver e-mail to an address like: last:first@domain.com

This requires that the ':' character now be allowed into the portion of the recipient field before the domain name. You could then modify @recipients to read:

@recipients = ('^[\w\-\.\:]+\@domain\.com');
BUT BE CAREFUL!!!!
Allowing certain characters could be VERY dangerous, especially if the characters are: %, <, >, (, ) or any newlines. You can read: http://web.nps.navy.mil/~miller/percent-hack.html
for information on exactly why the % character could be dangerous. And the document that prompted 1.91 explains why some of the others could lead to problems: http://www.monkeys.com/anti-spam/formmail-advisory.pdf

I ONLY WANT CERTAIN ADDRESSES TO WORK!

Let's say you only want yourself@yourdomain.com to be able to receive any form submissions. You should then set the @recipients array to:

@recipients = ('^yourself\@yourdomain\.com');
Now the only valid recipient is that one e-mail address.
If there are several, simply do:

@recipients = ('^user1\@yourdomain\.com',
'^user2\@their\.domain\.com');
CAN I USE SOMETHING EASIER?
Prior versions of FormMail recommended settings for @recipients like:

@recipients = ('domain.com','192.168.1.1'); OR
@recipients = ('^joe@somewhereelse.com');
The first is bad because it can be easily tricked by submitting a recipient such as spamvictim%elsewhere.com@domain.com. The second is MUCH better, but since it is used as a regular expression, and '.' can mean ANY character, a hacker could use joe@somewhereelseXcom to get past a valid recipient check. This is not a very big deal in most cases.
WHAT IS THIS ^ CHARACTER AND WHY SO MANY \'s??

In regular expressions, the ^ means "beginning of string". By default, FormMail places a $ at the end of the match, which means "end of string". By using both ^ and $ in regular expression matching, FormMail can match a string exactly. You only need to worry about including the ^, which is STRONGLY recommended for all regular expressions in the array.

The \ character is used to escape a character that otherwise means something special in regular expressions. For instance, you now see every '.' being escaped with a '\', as '.' means ANY CHARACTER, whereas '\.' requires that it match ONLY a period.

If you need a regular expression matching solution even more specific than the above examples explain, I recommend picking up a book on Perl.

Your formmail program is now configured.
Form Configuration
The action of your form needs to point towards this script (obviously), and the method must be POST or GET in capital letters. Version 1.5 of FormMail offers many new ways to code your form to tailor the resulting HTML page and the way the script performs. Below is a list of form fields you can use and how to implement them.

Necessary Form Fields

There is only one form field that you must have in your form, for FormMail to work correctly. This is the recipient field.

Field: recipient
Description: This form field allows you to specify to whom you wish for your form results to be mailed. Most likely you will want to configure this option as a hidden form field with a value equal to that of your e-mail address.

As of version 1.8, You can include multiple recipients by separating the values with commas.
Syntax: <input type=hidden name="recipient" value="email@your.host.com"> OR
<input type=hidden name="recipient" value="user@yourhost.com,user2@yourhost.com">

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Optional Form Fields

Field: subject
Description: The subject field will allow you to specify the subject that you wish to appear in the e-mail that is sent to you after this form has been filled out. If you do not have this option turned on, then the script will default to a message subject: WWW Form Submission.
Syntax: If you wish to choose what the subject is:
<input type=hidden name="subject" value="Your Subject">

To allow the user to choose a subject:
<input type=text name="subject">

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Field: email
Description: This form field will allow the user to specify their return e-mail address. If you want to be able to return e-mail to your user, I strongly suggest that you include this form field and allow them to fill it in. This will be put into the From: field of the message you receive. If you want to require an email address with valid syntax, add this field name to the required field.
Syntax: <input type=text name="email">

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Field: realname
Description: The realname form field will allow the user to input their real name. This field is useful for identification purposes and will also be put into the From: line of your message header.
Syntax: <input type=text name="realname">

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Field: redirect
Description: If you wish to redirect the user to a different URL, rather than having them see the default response to the fill-out form, you can use this hidden variable to send them to a pre-made HTML page.
Syntax: To choose the URL they will end up at:
<input type=hidden name="redirect" value="http://your.host.com/to/file.html">

To allow them to specify a URL they wish to travel to once the form is filled out:
<input type=text name="redirect">

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Field: required
Version: 1.3 & Up
Description: You can now require for certain fields in your form to be filled in before the user can successfully submit the form. Simply place all field names that you want to be mandatory into this field. If the required fields are not filled in, the user will be notified of what they need to fill in, and a link back to the form they just submitted will be provided.

To use a customized error page, see missing_fields_redirect
Syntax: If you want to require that they fill in the email and phone fields in your form, so that you can reach them once you have received the mail, use a syntax like:

<input type=hidden name="required" value="email,phone">

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Field: env_report
Version: 1.3 & Up
Description: Allows you to have Environment variables included in the e-mail message you receive after a user has filled out your form. Useful if you wish to know what browser they were using, what domain they were coming from or any other attributes associated with environment variables. The following is a short list of valid environment variables that might be useful:

REMOTE_HOST Sends the hostname making the request.
REMOTE_ADDR Sends the IP address of the remote host making the request.
REMOTE_USER If server supports authentication and script is protected, this is the username they have authenticated as. (This is not usually set.)
HTTP_USER_AGENT The browser the client is using to send the request.

There are others, but these are a few of the most useful. For more information on environment variables, see:
The CGI Resource Index: Documentation: Environment Variables
Syntax: If you wanted to find the remote host and browser sending the request, you would put the following into your form:

<input type=hidden name="env_report" value="REMOTE_HOST,HTTP_USER_AGENT">

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Field: sort
Version: 1.4 & Up
Description: This field allows you to choose the order in which you wish for your variables to appear in the e-mail that FormMail generates. You can choose to have the field sorted alphabetically or specify a set order in which you want the fields to appear in your mail message. By leaving this field out, the order will simply default to the order in which the browsers sends the information to the script (which is usually the exact same order as they appeared in the form.) When sorting by a set order of fields, you should include the phrase "order:" as the first part of your value for the sort field, and then follow that with the field names you want to be listed in the e-mail message, separated by commas. Version 1.6 allows a little more flexibility in the listing of ordered fields, in that you can include spaces and line breaks in the field without it messing up the sort. This is helpful when you have many form fields and need to insert a line wrap.
Syntax: To sort alphabetically:
<input type=hidden name="sort" value="alphabetic">

To sort by a set field order:
<input type=hidden name="sort" value="order:name1,name2,etc...">

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Field: print_config
Version: 1.5 & Up
Description: print_config allows you to specify which of the config variables you would like to have printed in your e-mail message. By default, no config fields are printed to your e-mail. This is because the important form fields, like email, subject, etc. are included in the header of the message. However some users have asked for this option so they can have these fields printed in the body of the message. The config fields that you wish to have printed should be in the value attribute of your input tag separated by commas.
Syntax: If you want to print the email and subject fields in the body of your message, you would place the following form tag:

<input type=hidden name="print_config" value="email,subject">

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Field: print_blank_fields
Version: 1.6 & Up
Description: print_blank_fields allows you to request that all form fields are printed in the return HTML, regardless of whether or not they were filled in. FormMail defaults to turning this off, so that unused form fields aren't e-mailed.
Syntax: If you want to print all blank fields:

<input type=hidden name="print_blank_fields" value="1">

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Field: title
Version: 1.3 & Up
Description: This form field allows you to specify the title and header that will appear on the resulting page if you do not specify a redirect URL.
Syntax: If you wanted a title of 'Feedback Form Results':

<input type=hidden name="title" value="Feedback Form Results">

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Field: return_link_url
Version: 1.3 & Up
Description: This field allows you to specify a URL that will appear, as return_link_title, on the following report page. This field will not be used if you have the redirect field set, but it is useful if you allow the user to receive the report on the following page, but want to offer them a way to get back to your main page.
Syntax: <input type=hidden name="return_link_url" value="http://your.host.com/main.html">

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Field: return_link_title
Version: 1.3 & Up
Description: This is the title that will be used to link the user back to the page you specify with return_link_url. The two fields will be shown on the resulting form page as:

return_link_title

Syntax: <input type=hidden name="return_link_title" value="Back to Main Page">

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Field: missing_fields_redirect
Version: 1.6 & Up
Description: This form field allows you to specify a URL that users will be redirected to if there are fields listed in the required form field that are not filled in. This is so you can customize an error page instead of displaying the default.
Syntax: <input type=hidden name="missing_fields_redirect" value="http://your.host.com/error.html">

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Field: background
Version: 1.3 & Up
Description: This form field allow you to specify a background image that will appear if you do not have the redirect field set. This image will appear as the background to the form results page.
Syntax: <input type=hidden name="background" value="http://your.host.xxx/image.gif">

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Field: bgcolor
Version: 1.3 & Up
Description: This form field allow you to specify a bgcolor for the form results page in much the way you specify a background image. This field should not be set if the redirect field is.
Syntax: For a background color of White:
<input type=hidden name="bgcolor" value="#FFFFFF">

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Field: text_color
Version: 1.3 & Up
Description: This field works in the same way as bgcolor, except that it will change the color of your text.
Syntax: For a text color of Black:
<input type=hidden name="text_color" value="#000000">

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Field: link_color
Version: 1.3 & Up
Description: Changes the color of links on the resulting page. Works in the same way as text_color. Should not be defined if redirect is.
Syntax: For a link color of Red:
<input type=hidden name="link_color" value="#FF0000">

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Field: vlink_color
Version: 1.3 & Up
Description: Changes the color of visited links on the resulting page. Works in the same way as link_color. Should not be set if redirect is.
Syntax: For a visited link color of Blue:
<input type=hidden name="vlink_color" value="#0000FF">

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Field: alink_color
Version: 1.4 & Up
Description: Changes the color of active links on the resulting page. Works in the same way as link_color. Should not be set if redirect is.
Syntax: For a active link color of Blue:
<input type=hidden name="alink_color" value="#0000FF">