<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta content="text/html;charset=UTF-8" http-equiv="Content-Type"></head><body ><div><font class="Apple-style-span" face="Verdana, arial, Helvetica, sans-serif"><span class="Apple-style-span" style="font-size: 12px;"><meta http-equiv="content-type" content="text/html; charset=utf-8"><div style="font-family: 'Times New Roman'; font-size: medium; "><font class="Apple-style-span" face="Verdana, arial, Helvetica, sans-serif"><span class="Apple-style-span" style="font-size: 12px; ">it's a normal desktop machines iptables firewall: </span></font></div><div style="font-family: 'Times New Roman'; font-size: medium; "><font class="Apple-style-span" face="Verdana, arial, Helvetica, sans-serif"><span class="Apple-style-span" style="font-size: 12px; "><br></span></font></div><div style="font-family: 'Times New Roman'; font-size: medium; "><font class="Apple-style-span" face="Verdana, arial, Helvetica, sans-serif"><span class="Apple-style-span" style="font-size: 12px; ">If i want to block udp on dport 80 on the output chain, then is this enough? i want to only allow tcp on it!</span></font></div><div style="font-family: 'Times New Roman'; font-size: medium; "><font class="Apple-style-span" face="Verdana, arial, Helvetica, sans-serif"><span class="Apple-style-span" style="font-size: 12px; ">iptables -P OUTPUT DROP</span></font></div><div style="font-family: 'Times New Roman'; font-size: medium; "><font class="Apple-style-span" face="Verdana, arial, Helvetica, sans-serif"><span class="Apple-style-span" style="font-size: 12px; ">iptables -A OUTPUT -o $PUBIF --dport 80 -j ACCEPT</span></font></div><div style="font-family: 'Times New Roman'; font-size: medium; "><font class="Apple-style-span" face="Verdana, arial, Helvetica, sans-serif"><span class="Apple-style-span" style="font-size: 12px; "><br></span></font></div><div style="font-family: 'Times New Roman'; font-size: medium; "><font class="Apple-style-span" face="Verdana, arial, Helvetica, sans-serif"><span class="Apple-style-span" style="font-size: 12px; ">or i need this rule?</span></font></div><div style="font-family: 'Times New Roman'; font-size: medium; "><font class="Apple-style-span" face="Verdana, arial, Helvetica, sans-serif"><span class="Apple-style-span" style="font-size: 12px; ">iptables -P OUTPUT DROP</span></font></div><div style="font-family: 'Times New Roman'; font-size: medium; "><font class="Apple-style-span" face="Verdana, arial, Helvetica, sans-serif"><span class="Apple-style-span" style="font-size: 12px; ">iptables -A OUTPUT -o $PUBIF -p tcp --dport 80 -j ACCEPT</span></font></div><div style="font-family: 'Times New Roman'; font-size: medium; "><font class="Apple-style-span" face="Verdana, arial, Helvetica, sans-serif"><span class="Apple-style-span" style="font-size: 12px; "><br></span></font></div><div style="font-family: 'Times New Roman'; font-size: medium; "><font class="Apple-style-span" face="Verdana, arial, Helvetica, sans-serif"><span class="Apple-style-span" style="font-size: 12px; ">the second one is the good one?</span></font></div></span></font></div><div id="" style="font-family: Verdana, arial, Helvetica, sans-serif; font-size: 12px; "></div></body></html>