Iptables implements packet filtering at the application layer

Iptables implements packet filtering at the application layer

Platform:
Linux5.4
Source code package:
Iptables-1.4.2.tar.bz2
L7-protocols-2008-10-04.tar.gz
Linux-2.6.25.19.tar.bz2
Netfilter-layer7-v2.20.tar.gz

Uninstall the original iptables. You can back up the iptables STARTUP script in advance and copy it later when you recompile iptables.
(/Etc/init. d/iptables)
Decompress the source code package to/usr/local/src;
Steps:
I. recompile the kernel
1. Merge kernel + layer7 Patches
# Tar jxvf linux-2.6.25.19.tar.gz2-C/usr/src/
# Tar zxvf netfilter-layer7-v2.20.tar.gz-C/usr/src/
# Cd/usr/src/linux-2.6.25.19/
# Patch-p1 </usr/src/netfilter-layer7-v2.20/kernel-2.6.25-layer7-2.20.patch
2. Configure the new kernel
# Cp/boot/config-2.6.18-8.el5. config
[The original kernel can be used or the kernel can be upgraded]
# Make menuconfig
[When configuring the kernel, pay attention to the following two points in "Networking ---> Networking Options ---> NetworkPacket filtering framework (Netfilter:
1) ---> Core Netfilter Configuration
// Compile "Netfilter connection tracking suport (NEW)" into a module (M). Select this option to see the configuration supported by layer7.
// Set layer7, string, state, time, IPsec, iprange, connlimit ...... Compile it into a module.
2) ---> IP: Netfilter Configuration
// Compile "IPv4 connection tracking support (require for NAT)" into a module.
// Compile "MASQUERADE target support" and "REDIRECT target support" under "Full NAT" into a module.
--->. Config
3. Compile and install modules and new kernels
# Make & make modules_install & make install
[After compilation and installation, restart and choose to use the new kernel (2.6.25.19) to boot the system]
Ii. recompile iptables
1. Uninstall existing iptables
# Rpm-eiptables -- nodeps

2. Merge iptables + layer7 Patches
# Tar jxvfiptables-1.4.2.tar.bz2-C/usr/src/
# CdS/usr/src/netfilter-layer7-v2.20/iptables-1.4.1.1-for-kernel-2.6.20forward/
# Cplibxt_layer7.c libxt_layer7.man/usr/src/iptables-1.4.2/extensions/

3. Compile and install
# Cd/usr/src/iptables-1.4.2/

#./Configure -- prefix =/-- with-ksource =/usr/src/linux-2.6.25.19
# Make & make install

4. Install the l7-protocols mode package
# Tar zxvfl7-protocols-2008-10-04.tar.gz-C/etc/
# Mv/etc/l7-protocols-2008-10-04/etc/l7-protocols

In this case, the test page has no rules:

For more details, please continue to read the highlights on the next page:

Recommended reading:

Linux Firewall iptables

Iptables + L7 + Squid implements a complete software firewall

Basic use of iptables backup, recovery, and firewall scripts

Detailed description of firewall iptables usage rules in Linux

Iptables usage Summary

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