Due to large amount of spammers on the internet today, many internet service providers have opted to block port 25 (the original port to send mail). This means that you would not be able to use web hosting companies to send mail. At Arvixe, we have a solution. By providing SMTP service on ports 26 and 587, we bypass the need to use port 25 and allow our customers to use our services despite the block placed by their ISPs.