What ports are open on my Linux Dedicated Server as default? gabe 7 years ago This article applies to Linux Dedicated Servers. This answer will list the default ports which are open for your Linux Dedicated Server. Dedicated Server Customers Only port 21 (ftp). port 53 (domain). port 80 (http). port 110 (pop3). port 23 (telnet). port 139 (netbios-ssn).