iptables allow creation of rules to define packet filtering behavior.

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348 views

List iptables rules as append command

A while back I was watching over the shoulder of a Linux guru and he issued a command that listed all the iptables rules in the format of the append commands you would need to issue in order to build ...
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1answer
1k views

Unable to make outbound SNMP connections when IPTables is enabled

I have a bunch of windows servers configured with the windows SNMP agent. Each server has four IP addresses and SNMP listens on all of them. There is something very odd with my monitoring server ...
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1answer
9k views

How to reset all iptables settings?

Are there any simpler commands to these? (e.g.: a oneliner? can one command reset iptables/netfilter settings to this?) IPTABLES="$(which iptables)" # RESET DEFAULT POLICIES $IPTABLES -P INPUT ...
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1answer
2k views

iptables/pf rule to only allow XY application/user?

I think there is no iptables/pf solution to only allow an XY application on e.g.: outbound tcp port 80, eth0. So if I have a userid: "500" then how could I block any other communications then the ...
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3answers
946 views

IP Tables / netfilters and modules

I am trying to understand how firewall works in linux... I have read documentation but i am not sure about some things.... Netfilters is included in the modern kernels which allows you using hooks ...
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3answers
6k views

Only allow certain outbound traffic on certain interfaces

I have rather an odd issue. I have a server with two network interfaces eth0 and eth1. Each are connected to a different network. Each network has a internet gateway. The server has various outbound ...
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2answers
8k views

iptables: allow certain ips and block all other connection

How do I allow certain ips and block all other connection in iptables?
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2answers
965 views

Screen session running as root? (it shouldn't be) node.js

cd /serv screen -R node {in the screen} node test.js C^a d initially, ls -l /dev/pts total 0 crw--w---- 1 tick-tock tty 136, 0 2011-04-19 16:41 0 crw--w---- 1 tick-tock tty 136, ...
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1answer
171 views

Linux App that monitors log and add rules to iptables

I used to use a linux software that monitors logs like http, ssh, etc and if it detects that someone is trying to use brute force, it blocks that ip by adding a rule to iptables. I forgot what that ...
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0answers
423 views

tun0+ iptables rule

I'm trying to figure out what that + sign means in a rule such as this: -A FORWARD -i tun0+ -j ACCEPT I'm pretty positive it relates to vpn. I noticed a /dev/net/tun interface and a tun0 in ...
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4answers
469 views

What does this iptables command do?

Does iptables -I INPUT -j ACCEPT open all ports?
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3answers
2k views

Is there a way to find which iptables rule was responsible for dropping a packet?

I have a system that came with a firewall already in place. The firewall consists of over 1000 iptables rules. One of these rule is dropping packets I don't want dropped. (I know this because I did ...
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1answer
370 views

1000 iptables entries on CentOS?

I just got a new dedicated server with CentOS and I'm trying to debug some network problems. In doing so, I found over one thousand iptables entries. Is this the default on a CentOS system? Is there ...
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2answers
784 views

iptables rule for local network with free internet blocking unrequested connection from internet to server?

I have a home server (with slackware 13) with a eth0 for the local network and a eth1 for the internet (cable modem with dynamic ip). While I do want to learn more about iptables I am still on the ...
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2answers
3k views

iptables log file

I have ubuntu and I want to know where can I find the log file of iptables? I find out /var/log/messages, but I am not sure this is a correct log file or not. And I also want to know when this log ...
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1answer
744 views

Sharing bandwidth between IPs

There are 200 users in my network, and these users are in two AD groups and cannot set specific IP ranges for each group. I want to set, for each group, the amount of bandwidth that can be shared ...
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2answers
137 views

Where to handle packets between clients?

"Server": 192.168.1.1 I want to "theoretically" disable that the clients can "ping" each other. Can i use an iptables rule for it? e.g.: iptables -A FORWARD -m iprange --src-range ...
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1answer
202 views

Is there a standard way to configure what policy iptables loads on startup under Debian?

I've just started playing with Debian 6.0 (Squeeze) in a VPS environment, as a way to learn more about system administration. One thing I'd like to configure is a default packet filtering policy. ...
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1answer
3k views

Using /etc/hosts or iptables to redirect site to https:// version

I'd like to have my system automatically take me to https://facebook.com even if I put http://facebook.com into my browser. I can get /etc/hosts to redirect to me to different domains, but it seems ...
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1answer
754 views

Control bandwidth with iptables

How can I control bandwidth in RHEL 5 using iptables?
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1answer
225 views

Bash script and Database

I have an iptables firewall in Linux bridge (RHEL5). I want to extract information like IP address, port number, port type, date and time, etc. from log messages using a Bash script, and then want to ...
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2answers
8k views

Reply on same interface as incoming?

I have a system with two interfaces. Both interfaces are connected to the internet. One of them is set as the default route; a side effect of this is that if a packet comes in on the non-default-route ...
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1answer
1k views

Dual network connection

I have a usb cellular modem and a Home LAN connection on my Ubuntu 10.10 box. Both work independently. I want to know how to have both connected at the same time, and be able to specify which ...
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1answer
469 views

How would I go about getting UPnP working on a Slackware server/firewall?

I'm a long time fan of Slackware and I've always had a machine serving as my main server/firewall with the latest version installed. I have it now but I'm struggling to find information on how to ...
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1answer
911 views

Shaping outgoing traffic with iptables

On my laptop, when I run any downloads, torrents, etc, browsing is crippled. I read somewhere that you could configure your iptables powered router to prioritize certain network traffic. Could I do ...
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1answer
2k views

Default mark for packets using iptables

I am trying to set up a QOS script on my Tomato-enabled WRT54G router. The script does the basics of what I need (make sure that a particular machine on my network has lower priority than anything ...
2
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1answer
822 views

iptables does not list rules i have created

I'm using this guide to set-up a shared internet connection between two PC's. At step 8 it says I should run the commands: iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE /etc/rc.d/iptables ...
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1answer
2k views

multigateway routing for specific src port

I have two gateway to access internet, somehow I want to load balancing it, so far its working, but some connection or service need persistent gateway IP to be used, so the client should never change ...
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2answers
467 views

Block specific IP from accessing gateway

Suppose you are on linux internet gateway/router. What would you do to block a client with specific IP using bash script. I prefer something like ./block_client.sh 192.168.1.123 to block and ...
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3answers
1k views

Can I limit a user (and their apps) to one network interface?

As the title really. I've actually got two scenarios to apply this: Multiseat Desktop: two network connections both with internet gateways and two accounts doing bandwidth-intensive tasks on each. I ...
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6answers
383 views

Recommend a reading for learning Linux firewalls configuration for beginner?

I am using Linux at home and want to be able to configure firewall. I would like to understand what I am doing not just copy paste some rules from internet :).