Disable & Verify Firewall

Fedora 20/21

Disable/stop Firewall

systemctl disable firewalld.service

systemctl stop firewalld.service

Can be undone with "start" and "enable".

Check Firewall in Fedora 20/21

systemctl status firewalld.service

Fedora 16

Add /bin/bash to /etc/shells as the vsftpd yum install does not do it correctly causing tftp timeout message

Debian/Ubuntu

sudo iptables -L

If disabled, the output should look like this:

Chain INPUT (policy ACCEPT)
target prot opt source destination 

Chain FORWARD (policy ACCEPT)
target prot opt source destination 

Chain OUTPUT (policy ACCEPT)
target prot opt source destination

Disable Ubuntu Firewall

sudo ufw disable

Disable Debian Firewall

iptables -F
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables -t mangle -F
iptables -t mangle -X
iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT
iptables -P FORWARD ACCEPT

Other debian settings:

etc/hosts.deny

This setting in the above file will deny traffic from any source except locally:

ALL:ALL EXCEPT 127.0.0.1:DENY

Comment out this line like so:

#ALL:ALL EXCEPT 127.0.0.1:DENY

Windows 7

Start -> Control Panel -> View by "Small icons" -> Windows Firewall -> Turn Windows Firewall On or Off -> Turn off all three.