Fedora Core 4 uses SELinux security. This can block access to and from your system. You can temporarily check to see if this security system is causing your problems by turning off the security system, testing your internet connectivity, then turning it back on. If SELinux is causing problems for your internet connection, you may reconfigure SELinux to permit specific actions, or use ipchains to control internet access. Also, it is possible (thouth unlikely) that your gateway machine is blocking access by your linux computer.
To check SELinux use the following command (from text login or Applications, System Tools, Terminal )
If you are not root type "su -" and press ENTER (without the "s) and enter the root password when prompted. This will change the terminal prompt to [root@machinename ~]#
Type "vi /etc/selinux/config" and press ENTER
Arrow down to the line that reads
SELINUX=enforcing (may be enforcing, permissive, or disabled)
If it is disabled then this is NOT your problem. If it is not disabled then change it to disabled and retry. If you are not familiar with the vi editor move the cursor to the first character after the = then type "cw" The editor will remove the word after the = and put you in insert mode so you can type (change word command) Type the word you need to insert here ie: disabled, then press ESC to exit insert mode and :x to exit and save your changes. If you accidentally cbange something you don't want to change press ESC :q! to quit without saving, then try again.
