client receiving spam through contact form

Hello

I have installed "fast secure contact form" on a client's website.
client says he is receiving spam messages through the form, and he is asking me if we can block it. so I wanted to find out if there is a good way of doing this.

I can block their ip via htaccess, but they can easily change their ip
I can block any messages containing links, but then a legit user won't be able to send links.

what else can I do? am I missing anything?

I would call your host, they are good with stuff like that usually. Or add some crazy captcha software, or change plugin to paid online form that combats spam.

Well, there's always the posbility of adding a captcha requirement to the contact form.
That should decrease the spam significantly. I would also IP block them via the htaccess
(although, the captcha by itself should take care of them)

Add a captcha, it will cut down on the spam. But there will always be spam out there.

If he/she is getting hundreds of spam emails daily then you need to change it and monitor it to see what's going on. If they're just getting one or two then it's not much to worry about.

Yeah add a captcha, there are bots that scour the web looking for those contact forms to spam.

you can add captcha and install akismet if you are using wordpress.

Akismet works on forms too.

I was recently getting the same thing. I added recaptcha and took care of all but about 1 or 2 spam messages a week. I was getting a few per day

1. add a captcha.
2. block them by geoip script if they're overseas.

You could either add a captcha field in the contact form or if you can't, replace the contact form with one which has captcha protection built in and that should pretty much take care of the spam emails/messages.

What type of spam if it (ie: automatically generated etc).

Three methods that would drastically reduce spam rates:

1) Captcha as mentioned above, but try a simple checkbox that simply notifies that the user is not spam as it has a higher reduction than most general CAPTCHAs whilst providing no drop off by increasing the barrier of entry
2) Install Honeypot on that form page. Honeypot is basically an invisible form in which auto-form fillers max out but users won't fill.
3) If it's manual submission, then the best thing you can do is to kill the footprints that lead them you your website. The easiest way to do this is the find your standard "leave a reply" footprints and replace them with Data URIs so that scrapers can't read them but users can. So in the RAW HTML, instead of writing "Leave a Reply", you'd input this: