IP sets are a framework inside the Linux 2.4.x and 2.6.x kernel, which can be administered by the ipset utility. Depending on the type, currently an IP set may store IP addresses, (TCP/UDP) port numbers or IP addresses with MAC addresses in a way, which ensures lightning speed when matching an entry against a set. If you want to
- Store multiple IP addresses or port numbers and match against the collection by iptables at one swoop;
- Dynamically update iptables rules against IP addresses or ports without performance penalty;
- Express complex IP address and ports based rulesets with one single iptables rule and benefit from the speed of IP sets then ipset may be the proper tool for you.
Installation
First turn on EPEL repo and type the following yum command:
# yum install ipset
Sample outputs:
Loaded plugins: auto-update-debuginfo, protectbase, rhnplugin 0 packages excluded due to repository protections Setting up Install Process Resolving Dependencies --> Running transaction check ---> Package ipset.x86_64 0:6.11-1.el6 will be installed --> Processing Dependency: libmnl.so.0(LIBMNL_1.0)(64bit) for package: ipset-6.11-1.el6.x86_64 --> Processing Dependency: libmnl.so.0()(64bit) for package: ipset-6.11-1.el6.x86_64 --> Running transaction check ---> Package libmnl.x86_64 0:1.0.3-4.el6 will be installed --> Finished Dependency Resolution Dependencies Resolved =================================================================================== Package Arch Version Repository Size =================================================================================== Installing: ipset x86_64 6.11-1.el6 rhel-x86_64-server-6 61 k Installing for dependencies: libmnl x86_64 1.0.3-4.el6 epel 22 k Transaction Summary =================================================================================== Install 2 Package(s) Total download size: 82 k Installed size: 46 k Is this ok [y/N]: y Downloading Packages: (1/2): ipset-6.11-1.el6.x86_64.rpm | 61 kB 00:00 (2/2): libmnl-1.0.3-4.el6.x86_64.rpm | 22 kB 00:00 ----------------------------------------------------------------------------------- Total 172 kB/s | 82 kB 00:00 Running rpm_check_debug Running Transaction Test Transaction Test Succeeded Running Transaction Installing : libmnl-1.0.3-4.el6.x86_64 1/2 Installing : ipset-6.11-1.el6.x86_64 2/2 Verifying : libmnl-1.0.3-4.el6.x86_64 1/2 Verifying : ipset-6.11-1.el6.x86_64 2/2 Installed: ipset.x86_64 0:6.11-1.el6 Dependency Installed: libmnl.x86_64 0:1.0.3-4.el6 Complete! |
Examples
Type the following commands:
## create ip set called badips (-N) ## ## Uses a hash to store IP host addresses or network ## ## addresses. Zero valued IP address cannot be stored ## ## in a iphashtype of set. ## ipset -N badips iphash ## add IP address ## ipset -A badips 202.54.1.2 ipset -A badips 203.54.1.2 ## drop all ip address stored in ipset called badips ## iptables -A INPUT -m set --set badips src -j DROP |
The recommended syntax is as follows:
# ipset create myblacklist hash:ip hashsize 4096
# iptables -A INPUT -m set --set myblacklist src -j DROP
Now, you can add IP address as follows:
# ipset add myblacklist 192.168.1.2
# ipset add myblacklist 202.54.1.1
# ipset add myblacklist 202.54.1.3
ipset has command has many more options. See man page for more details:
# man ipsets
3 comment
Hi,
Thanks a lot, very nice article..
Hello, I need a step by step tutorial about blocking countries with ipset on CentOS 6.
Thank you.
Raul, if you get that info, please let me know too. I use shorewall and would live to do exactly that.