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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 )

Linux Network IP Accounting

I need to know how much data are transmitted on my ppp0 network or eth0 Internet links? How do I set IP accounting by address such as 123.1.2.3 and 123.1.2.4? How do I set IP accounting per Apache virtual domain? How do I set accounting by service port (http, smtp) and protocol (tcp, udp, icmp)? How do I record how much traffic each of the clients computer is using?
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iptables: Read a List of IP Address From File And Block

How do I read a list of ip address (subnets) using a text file and block all of them using Linux iptables command?
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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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