Archívy značky: firewall

Firewall rule to allow access to windows updates

When you try to install Windows updates for the first time (e.g. you buy a new computer with Windows 8.1 preinstalled), windows doesn’t start to download updates unless you permit UDP connection to port 3544.

Here is the firewalling rule for your linux firewall:


iptables -A FORWARD -d 94.245.64.0/18 -p udp -m udp --dport 3544 -m conntrack --ctstate NEW -j ACCEPT

Here we go!
Windows_update

Shorewall – filtering IMAP/SMTP access to gmail.com domain

gmail-firewall-IMAPDo you need to discover what IP netblocks are owned and operated by Google to perhaps add to your firewall ACLs?

With dynamic zones available in Shorewall, you are able to define firewall rules and to filter network traffic based on the domain name. For example, you can permit IMAPS connection only to gmail.com domain. Problem is that Google cluster is very big and you are always connecting to different IP address. So you can’t define static rules for traffic filtering.

Here is little HOWTO do this.
Pokračovať v čítaní