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Linux Netfilter Tutorials

Tutorials, howtos and tips about Linux netfilter/iptables firewall includes examples, configurations, blocking traffic and IP address, opening and closing ports, and much more. ( rss feed )

Disable / Turn Off Firewall in Ubuntu Linux Server

How do I disable the firewall in Ubuntu Linux server edition? How do I turn off the firewall in Ubuntu Linux version 12.04 or 14.04 LTS server?
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tc: Linux HTTP Outgoing Traffic Shaping (Port 80 Traffic Shaping)

I've 10Mbps server port dedicated to our small business server. The server also act as a backup DNS server and I'd like to slow down outbound traffic on port 80. How do I limit bandwidth allocation to http service 5Mbps (burst to 8Mbps) at peak times so that DNS and other service will not go down due to heavy activity under a Linux operating systems?
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Iptables Limits Connections Per IP

How do I restrict the number of connections used by a single IP address to my server for port 80 and 25 using iptables?
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Linux iptables: Port Redirection Example

How do I redirect 80 port to 8123 using iptables?
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Iptables: Invert IP, Protocol, Or Interface Test With !

How do I invert a protocol or ip address test while writing iptables based shell scripts?
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Linux Iptables: Add / Delete An IP Address Remotely Using A Shell Script

I've root ssh access and need to add / delete a few IP address on fly using the IPtables command via local shell script. How do I add or delete an IP address remotely over the SSH session under CentOS / Redhat / RHEL / Debian / Ubuntu Linux?
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Samba: Linux Iptables Firewall Configuration

How do I configure iptables firewall under CentOS / Fedora / RHEL / Redhat Linux to allow access to the Samba server? How do I open TCP ports # 137, 138, 139 and 445 under Linux so that all Microsoft Windows machine can access files and printer on a Linux host?
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CentOS / RHEL IPv6 ip6tables Firewall Configuration

I know how to configure iptables (IPv4) host-based firewall using Netfilter. How do I configure ip6tables for basic filtering IPv6 packets?
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Apache IPv6 Configuration: Dual Stacked IPv4 & IPv6 Virtual Hosts

How do I configure Apache IPv6 networking under a UNIX / Linux / BSD operating system? How do I configure httpd IPv6 and IPv4 under a RHEL / CentOS / Fedora / Debian / Ubuntu Linux?
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DenyHosts: Remove / Delete an IP address

I've followed your guide and installed denyhosts to protect on my RedHat 5.3 OpenSSH based server. However, I've been accidentally blocked out from my home ADSL IP address. I tried removing my blocked IP from /etc/hosts.deny, but it did blocked it again quickly. It appears that DenyHosts keeps track of the attempts somewhere on disk or memory. How do I remove my own home IP address from DenyHosts?
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