Solved

iptables limit connection per ip correct way ?

Posted on 2016-08-29
2
333 Views
Last Modified: 2016-11-20
i have set some rules in ip tables as example i added

iptables -A INPUT -p tcp --syn --dport 22 -m connlimit --connlimit-above 4 --connlimit-mask 32 -j REJECT --reject-with tcp-reset

Open in new window


and thats how my iptables looks like

Chain INPUT (policy ACCEPT)
target     prot opt source               destination
REJECT     tcp  --  anywhere             anywhere             tcp dpt:20000 flags:FIN,SYN,RST,ACK/SYN #conn src/32 > 2 reject-with tcp-reset
REJECT     tcp  --  anywhere             anywhere             tcp dpt:ssh flags:FIN,SYN,RST,ACK/SYN #conn src/32 > 2 reject-with tcp-reset

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

Open in new window



but there is always ips by-pass the limit and they go up to 400 connection per ip

what is the correct way to limit the connection per ip ?

i am running Ubuntu 15.04 server
0
Comment
Question by:dolphin King
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 
LVL 37

Accepted Solution

by:
bbao earned 500 total points
ID: 41776606
not sure if your Linux distribution supports "--iplimit-mask n" option which sets the number of bits n of IP addresses that will be masked off? if n is 32, then it should be per IP based control.
0
 

Author Comment

by:dolphin King
ID: 41777138
its support the iplimit mask normally i couldn't connect with more than 3 times the third time i got disconnect but there is some ips couldnt response to this connection limit
0

Featured Post

Why Off-Site Backups Are The Only Way To Go

You are probably backing up your data—but how and where? Ransomware is on the rise and there are variants that specifically target backups. Read on to discover why off-site is the way to go.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

The DROP (Spamhaus Don't Route Or Peer List) is a small list of IP address ranges that have been stolen or hijacked from their rightful owners. The DROP list is not a DNS based list.  It is designed to be downloaded as a file, with primary intention…
The purpose of this article is to fix the unknown display problem in Linux Mint operating system. After installing the OS if you see Display monitor is not recognized then we can install "MESA" utilities to fix this problem or we can install additio…
Connecting to an Amazon Linux EC2 Instance from Windows Using PuTTY.
This demo shows you how to set up the containerized NetScaler CPX with NetScaler Management and Analytics System in a non-routable Mesos/Marathon environment for use with Micro-Services applications.

724 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question