How To: Disable Firewall on RHEL / CentOS / RedHat Linux

How To: Disable Firewall on RHEL / CentOS / RedHat Linux

by  on OCTOBER 10, 2007 · 24 COMMENTS· last updated at JUNE 28, 2012

I don’t want firewall because I only run one http (port 80) public service. How do I turn off or disable firewall permanently under RHEL / Fedora Linux / Red Hat Enterprise Linux and CentOS Linux?
iptables is administration tool / command for IPv4 packet filtering and NAT. You need to use the following tools:
[a] service is a command to run a System V init script. It is use to save / stop / start firewall service.
[b] chkconfig command is used to update and queries runlevel information for system service. It is a system tool for maintaining the /etc/rc*.d hierarchy. Use this tool to disable firewall service at boot time.

How Do I Disable Firewall?

First login as the root user.
Next enter the following three commands to disable firewall.
# service iptables save
# service iptables stop
# chkconfig iptables off

If you are using IPv6 firewall, enter: Continue reading How To: Disable Firewall on RHEL / CentOS / RedHat Linux

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Mekanisme IP Port Forward di Linux, Mikrotik, Windows

IP & Port Forwarding. Mekanisme port forward adalah sebuah cara untuk melakukan penerusan paket ke tempat lain, tanpa client perlu mengetahui dan merasakan bahwa sebenarnya paket itu bukan ditembak ke server tujuan dari client. Melainkan dialihkan ke server yang lain.
Konfigurasi : CLIENT —>SERVER (published) —> SERVER (local)

Mekanisme untuk melakukan Port Forwarding adalah sebagai berikut :
1. LINUX
http://www.uday.com.np/tools/iptables.php (ini untuk wizard secara visualisasi)
http://linux.about.com/od/ipm_howto/a/hwtipm52t00.htm (ini script otomatisnya)
Contoh Kasus :

1). Kita ingin mengalihkan seluruh request dari client yang masuk dengan port 15035 menuju ke 192.168.121.5:15035
# iptables -t nat -I PREROUTING -p tcp –dport 15035 -j DNAT –to 192.168.121.5
Contoh lain :
# iptables -t nat -A PREROUTING -p tcp –dport 90080 -j DNAT –to 10.4.1.15:80
Contoh lain :
# iptables -t nat -A PREROUTING -d 192.168.204.90 -j DNAT –to-destination 10.19.184.2
# iptables -A FORWARD -j LOG –log-prefix ‘DROPPING: ‘ –log-level info
# tail -fn100 /dev/log/messages | grep DROPPING
2). Kita ingin menjalankan APACHE TOMCAT yang berjalan secara lokal di port 8080, tetapi kita ingin menampilkan keluar sebagai port 80 tanpa merubah konfigurasi TOMCAT, tetapi menggunakan iptables.
# iptables –table nat –append PREROUTING –protocol tcp –destination-port 80 –in-interface eth0 –jump REDIRECT –to-port 8080
Catatan:
Aturan diatas tidak bisa melakukan redirect permintaan lokal. Karena menggunakan perintah PREROUTING. Jika ada client yang jalan langsung di server, maka gunakan port 8080.
2. MIKROTIK
Berikut ini mekanisme untuk membelokkan paket dari server 202.162.111.111:80 ke 10.14.1.101:8080
/ip firewall nat add chain=dstnat dst-address=202.162.111.111 protocol=tcp dst-port=80
action=dst-nat to-addresses=10.14.1.101 to-ports=8080
3. WINDOWS
Biasanya saya menggunakan aplikasi Free dari Internet untuk tujuan ini, yaitu :
– http://www.simpleportforwarding.com/
– http://www.quantumg.net/portforward.php