interface openSUSE emang berbeda sekali dari pengaturan Enable/Disable yang muda dengan YaST, nah kali ini saya kan memberikan cara menonaktifkan firewall ( enable / disable Firewall ) pada ubuntu 11.10 / 12.04 LTS / 12.10
Tahap – tahap nya :
- Buka terminal
- Untuk mematikan firewall
sudo ufw disabled
- Untuk menghidupkan kembali
sudo ufw enabled
Lao lebih jelas bisa melihat referensi dari HELP UBUNTU :
The Linux kernel includes the Netfilter subsystem, which is used to manipulate or decide the fate of network traffic headed into or through your server. All modern Linux firewall solutions use this system for packet filtering.
The kernel’s packet filtering system would be of little use to administrators without a userspace interface to manage it. This is the purpose of iptables. When a packet reaches your server, it will be handed off to the Netfilter subsystem for acceptance, manipulation, or rejection based on the rules supplied to it from userspace via iptables. Thus, iptables is all you need to manage your firewall if you’re familiar with it, but many frontends are available to simplify the task.
ufw – Uncomplicated Firewall
The default firewall configuration tool for Ubuntu is ufw. Developed to ease iptables firewall configuration, ufw provides a user friendly way to create an IPv4 or IPv6 host-based firewall.
ufw by default is initially disabled. From the ufw man page:
“ ufw is not intended to provide complete firewall functionality via its command interface, but instead provides an easy way to add or remove simple rules. It is currently mainly used for host-based firewalls. ”
The following are some examples of how to use ufw:
· First, ufw needs to be enabled. From a terminal prompt enter:
· To open a port (ssh in this example):
· Rules can also be added using a numbered format:
· sudo ufw insert 1 allow 80
· Similarly, to close an opened port:
· To remove a rule, use delete followed by the rule:
· sudo ufw delete deny 22
· It is also possible to allow access from specific hosts or networks to a port. The following example allows ssh access from host 192.168.0.2 to any ip address on this host:
· sudo ufw allow proto tcp from 192.168.0.2 to any port 22
Replace 192.168.0.2 with 192.168.0.0/24 to allow ssh access from the entire subnet.
· Adding the –dry-run option to a ufw command will output the resulting rules, but not apply them. For example, the following is what would be applied if opening the HTTP port:
· sudo ufw –dry-run allow http
· :ufw-user-input – [0:0]
· :ufw-user-output – [0:0]
· :ufw-user-forward – [0:0]
· :ufw-user-limit – [0:0]
· :ufw-user-limit-accept – [0:0]
· ### tuple ### allow tcp 80 0.0.0.0/0 any 0.0.0.0/0
· -A ufw-user-input -p tcp –dport 80 -j ACCEPT
· -A ufw-user-input -j RETURN
· -A ufw-user-output -j RETURN
· -A ufw-user-forward -j RETURN
· -A ufw-user-limit -m limit –limit 3/minute -j LOG –log-prefix “[UFW LIMIT]: “
· -A ufw-user-limit -j REJECT
· -A ufw-user-limit-accept -j ACCEPT
· ufw can be disabled by:
· To see the firewall status, enter:
· And for more verbose status information use:
· sudo ufw status verbose
· To view the numbered format:
· sudo ufw status numbered
|If the port you want to open or close is defined in /etc/services, you can use the port name instead of the number. In the above examples, replace 22 with ssh.
This is a quick introduction to using ufw. Please refer to the ufw man page for more information.
ufw Application Integration
Applications that open ports can include an ufw profile, which details the ports needed for the application to function properly. The profiles are kept in /etc/ufw/applications.d, and can be edited if the default ports have been changed.
· To view which applications have installed a profile, enter the following in a terminal:
· Similar to allowing traffic to a port, using an application profile is accomplished by entering:
· An extended syntax is available as well:
· ufw allow from 192.168.0.0/24 to any app Samba
Replace Samba and 192.168.0.0/24 with the application profile you are using and the IP range for your network.
|There is no need to specify the protocol for the application, because that information is detailed in the profile. Also, note that the app name replaces the port number.
· To view details about which ports, protocols, etc are defined for an application, enter:
· sudo ufw app info Samba
Not all applications that require opening a network port come with ufw profiles, but if you have profiled an application and want the file to be included with the package, please file a bug against the package in Launchpad.