Duc Hoang’s Blog

Mot kinh nghiem muon chia se cung cac ban web master khi bi spam qua contact form. Spammers muon spam email qua contact form cua ban khong nhat thiet phai vao trang contact.php cua ban va fill vao tung input. Ho co the de dang dung hard code qua URL de send mot message toi email cua ban, chang han nhu

http://yourdomain.com/contact.php?message=gotcha&email=anything@anything.com&…

Spammers co the dung google de tim ra hang tram trang contact.php roi send randomly chu chua chac la ho nham truc tiep vao ban.

Ho dung phan mem de tu dong gui spam den contact form cua ban, luc do hom thu cua ban se bi flood va khong biet email nao la spam, email nao la email cua ban. Minh muon chia se cach chong spam trong truong hop nay voi cac ban.

Cach thu 1: che`n mot dong code vao contact form $_SERVER[‘REMOTE_ADDR’], ban co the lay duoc IP cua nguoi gui spam. Sau do ban dung Firewall va chan IP cua spammer.

Cach thu 2:

+ Da so lap trinh vien dung ten contact.php hoac email.php cho trang contact. Day chinh la keywords de spammers tim thong tin qua google, vi vay ban hay doi ten trang do toi mot ten khac chang han nhu nospam.php. Buoc nay tam thoi co the chan duoc spammers trong 1 thoi gian ngan, neu spammers muon spam trang web cua ban thi ho chi can vao trang web cua ban va click vao link de tim ra ten file (hoac chinh google se index lai link tren trang web cua ban) vi vay ban hay lam buoc tiep theo de hoan toan loai bo spam.

+ Dung code validation truoc khi cho phep gui message. Noi nom na la dung 1 picture trong do chua cac chu cai, nguoi gui muon gui message di thi phai go dung nhung chu cai trong buc anh do. Neu go sai thi message se khong duoc gui di. Vi spammer dung software de gui message cho nen se khong doc duoc nhung chu cai trong buc anh. Ban co the dung code cua Recaptcha ( http://recaptcha.net/ ) cho website cua ban.

100% warranty chong spam (cho toi thoi diem nay :D).

Day la kinh nghiem thuc te cua minh muon chia se cung cac ban, neu cac ban co cach nao hay hon thi comment cho minh biet voi nhe.