1
vote
1answer
52 views

How can I protect my computer when the only way to access the internet is though a compromised internet connection?

I access the network through a connection which is most likely compromised by a MITM attack. I can't do much about it. What steps should I take to lessen the influence of this attack. I'm especially ...
3
votes
1answer
39 views

nc both fails and succeeds

Platform: RHEL 5.10 netcat Version: 1.84-10.fc6 I was trying to figure out if my inability to ssh was TCP-level and usually I use nc for this. This time, however, I got something unexpected. ...
0
votes
2answers
176 views

Isolate a hosts networking with iptables

I want to isolate a host on my home intranet using iptables on my linux router. So say for instance, I have a host that has the IP of 10.0.1.50 and I want it to be able to talk to the rest of the ...
1
vote
0answers
129 views

Full network logging via linux firewall ( iptables )?

How truly enable full network logging via iptables? There is an option --log-prefix to add a tag to log entries. But the log entries don't show all complete packets. What a grand way to enable full ...
2
votes
0answers
502 views

openwrt firewall - block a set of ip addresses from internet access

I'm running OpenWRT Attitude Adjustment r33556 / LuCI Trunk (trunk+svn9325) on my WNDR3800. I would like to configure my firewall to: Only allow a specific range of IP addresses to access internet, ...
0
votes
0answers
34 views

Custom firewall zone

Is there a way to create a custom zone using firewall-cmd in fedora. They give you some predetermined zones, but no way to create a custom zone with a custom name and add rules to that zone. Is ...
2
votes
1answer
50 views

RapidIO packet filtering in Linux

I was wondering if there is support in Linux Kernel for RapidIO packets filtering, something similar to iptables, but based on RapidIO header?
2
votes
3answers
688 views

How to setup transparent firewall using ArchLinux

I am trying yo setup a Transparent Firwall using ArchLinux. My setup looks like this: (ISP, IP: 10.90.10.254) \ \ \ (eth0-> ip: 10.90.10.1 gateway: 10.90.10.254) +-----------+ | ...
3
votes
1answer
2k views

IPTables - Port to another ip & port (from the inside)

I currently have a NAS box running under port 80. To access the NAS from the outside, I mapped the port 8080 to port 80 on the NAS as follow: iptables -t nat -A PREROUTING -p tcp --dport 8080 -j DNAT ...
2
votes
3answers
551 views

Linux stack for a home network firewall/proxy?

I've got a generic home 'network' where my ISP supplied modem acts as router with a software firewall built-in. My PCs connect directly to this router to access the Internet. I want to place a box in ...
1
vote
1answer
168 views

How to allow access to web only through proxy?

I have a machine with Linux Slackware 13.37. Is it possible to configure iptables, so the users will be able to access web only through squid? The direct access through the browser will be blocked. ...
1
vote
1answer
688 views

Help to understand Iptables Forward chain with DNAT

I have one server where iptables configured with all chains DROP in filter table eth0 :- 10.0.0.2 [ Intranet assume as LAN ] eth2 :- 172.16.0.2 [ External clients assume as WAN ] Now What I am ...
1
vote
2answers
2k views

iptables blocking from internet side on eth1?

How to use iptables to deal with two Ethernet ports? eth0 port for LAN use (192.168.1.50 Private IP). eth1 port is connected to the internet via cable modem (80.0.xxx.xxx public IP). ifconfig ...
3
votes
1answer
2k views

How to understand why the packet was considered INVALID by the `iptables`?

I set up some iptables rules so it logs and drops the packets that are INVALID (--state INVALID). Reading the logs how can I understand why the packet was considered invalid? For example, the ...
1
vote
1answer
280 views

Firewall/routing rule in Centos for this setup

I have two ethernet interfaces, namely eth0 and eth1. I want to implement an advanced routing rule but I am totally new to firewall/routing rules in CentOS. Here is what I am trying to do: Both my ...
3
votes
3answers
600 views

Can't add large number of rules to iptables

I made a very simple bash script (echo at start, runs commands, echos at end) to add approx 7300 rules to iptables blocking much of China and Russia, however it gets through adding approximately 400 ...
3
votes
1answer
528 views

How to “jail” a user account's network capabilities on Linux?

Linux box a is connected to a home DSL line with dynamic DNS registration, hosting a tmux session to which multiple clients connect in read-only mode over SSH. All users connect using the same ...
6
votes
3answers
6k views

What prevents a machine from responding to pings?

I have a CentOS release 5.4 linux box on Amazon EC2 that I'm trying to set up to be monitored via Nagios. The machine is in the same security group as the nagios server, but it seems to be ...
3
votes
1answer
1k views

Is berkeley packet filter ported to linux?

I am doing some research to figure out what distro's of linux contain kernel packet filtering and are compatible with BPF. http://kernelnewbies.org/Linux_3.0 http://lwn.net/Articles/437981/ These ...
1
vote
1answer
1k views

Redirect http using iptables for an ip range

I have a range of ip addresses (10.13.13.10-19) that I want to redirect all outgoing http traffic to an internal webserver. So if someone in that range tried to access any site, the html from my ...
5
votes
1answer
4k views

Uncomplicated Firewall (UFW) and UPNP

Is it possible to configured UFW to allow UPNP between computers in the home network? Everything works if I turn off the firewall. I can see in syslog the firewall is blocking me. I've tried all ...
0
votes
2answers
2k views

How to set up firewall on Debian Squeeze

I have set up Apache, MySQL, PHP, SSH (which I use to connect to the VPS), Node.js, MongoDB and ProFTPd. Now, I want to have a firewall on the system, so that no one hacks the system. For instance, ...
0
votes
1answer
2k views

IPtables string match

I'm trying to write iptables string match rule To block http://domain.com:8888 and https://domain.com:8888 when it matches the supplied string in the rule. And another rule to redirect the ports also ...
1
vote
1answer
154 views

Linux tools to choose suitable Cisco ASA 5500

I have a linux webhosting server which attracts DDOS attacks. I want to use Cisco ASA 5500 Series Adaptive Security Appliances to protect the linux server from them. I know there are many factors ...
0
votes
2answers
166 views

How To See Which Ports Are Open On A Particular Firewall

Using the terminal I was wondering if it would be possible to see a list of all the active firewalls on a particular system that I have shelled into. I want to be able to see which ports are active ...
1
vote
1answer
378 views

How do I shut down ports remotely without shutting myself out?

I have an Ubuntu 11.04 server in a remote location on another continent, so I have no physical access to it. I only interact with it by ssh (and scp), and intend to only ever interact with it that ...
3
votes
1answer
613 views

Linux Home Firewall

I was recently delving into thoughts of building a small home server to run random things off of (maybe a TF2 server). Thinking about this further I realized I would need to get a better firewall ...
1
vote
1answer
171 views

iptable rule to redirect only https handshake?

I was reading this interesting article today: http://www.moserware.com/2009/06/first-few-milliseconds-of-https.html A crazy thought came to mind...Is it possible to write an iptable rule that only ...
5
votes
2answers
2k views

Preventing program from using internet

Is there a way to block certain programs from being able to connect to the internet in Debian (a firewall blocking outgoing connections), so for example, to block a windows program running in wine ...
8
votes
4answers
681 views

iptables on tor exit node

I want to run an open Tor router. My exit policy will be similar to ReducedExitPolicy. But I also want to make it hard for the tor network to abuse my resources. Cases I want to prevent clients ...
2
votes
0answers
693 views

pfsense long ping to google

I have a pfsense box set up. What happens is I set a rule so I can't hit the admin interface 192.168.3.1 from the box. With the rule enabled --- www.l.google.com ping statistics --- 2 packets ...
4
votes
2answers
322 views

How can I use one network port for VPN and the other for everything else?

My Linux machine has two network ports with two IP addresses. I want to use one port for my VPN and accounting, and the other port for other usages. How can I tell Linux not to allow any requests from ...
3
votes
2answers
498 views

How to listen to all ports (UDP and TCP) or make them all appear open in Debian

I got an external Debian server. The problem is that my university campus doesn't allow connections to go outside when the port is different than TCP port 22, 80, 443, or UDP port 123. I tested them ...
3
votes
2answers
376 views

Recommended reverse firewall applications for linux?

I'm looking for a reverse firewall, something like Little Snitch for Linux, but my google-fu is failing me. Does something like this exist on Linux?
0
votes
1answer
624 views

Can't connect remotely to server running redhat (ec2)

I created a RedHat 6.1 VM with EC2. Logged in as root, I installed (unzipped) JDK1.7 in /root/bin/jdk1.7.0 and installed (unzipped) GlassFish 3.1.1 in /root/bin/glassfish3. I set JAVA_HOME and ...
-1
votes
1answer
6k views

What is sport and dport?

I want to stop internet on my system using iptables so what should I do? iptables -A INPUT -p tcp --sport 80 -j DROP or iptables -A INPUT -p tcp --dport 80 -j DROP ?
4
votes
2answers
1k views

What tools do I need to intercept and change an incoming packet on a WP2-Personal wifi hub

Which tools should I research into to intercept a plain text packet, edit it and then continue it on it's way. I am using Ubuntu 11.04 and Backtrack 5; my wifi is WPA2-person encrypted. I need to edit ...
6
votes
2answers
465 views

Configuring a vncserver so it's only accessible from my ssh tunnel

Since I use vnc through an ssh tunnel, is there any way I can block the open vnc port that the remote machine is listening on without it affecting my ability to use the ssh tunnel? Both machines are ...
2
votes
3answers
358 views

Port monitoring on GNU/Linux based NAT router

I am using a Ubuntu machine as a NAT router. How can I find out the following: the ports on which the LAN machines are listening or communicating (both tcp and udp); which local machines have ...
6
votes
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?
3
votes
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 ...
2
votes
4answers
469 views

What does this iptables command do?

Does iptables -I INPUT -j ACCEPT open all ports?
1
vote
2answers
783 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 ...
4
votes
3answers
313 views

Is it possible to simulate “no external access” from a Linux machine when developing?

Sometimes I upload an application to a server that doesn't have external internet access. I would like to create the same environment in my machine for testing some features in the application and ...
3
votes
3answers
272 views

Turning an old computer into a network firewall

I have an old Dell Dimension with two ethernet cards, and I need to turn it into a firewall. I've tried FireStarter and IPCop, but I don't think I'm setting them up right. Here's the setup that I'm ...
0
votes
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 ...
1
vote
1answer
954 views

IPTABLES rule for separating users

I have an OpenWrt 10.03 router [ IP: 192.168.1.1 ], and it has a DHCP server pool: 192.168.1.0/24 - clients are using it through wireless/wired connection. Ok! Here's the catch: I need to separate ...
6
votes
3answers
357 views

SpamAssassin Under Linux VPS

I am getting bald with this guys: On a Linux VPS (CentOS), I have setup a mail server (Exim+Dovecot+Clamav+SpamAssassin) but scanning mail for spam using SpamAssassin is proving to be a challenge. I ...
-1
votes
1answer
1k views

How can I open port 21 on a Linux VM?

I need to open port 21 on a Linux (CentOS 5) virtual machine I have. I have tried several Google solutions, but none are working. I was wondering if someone could tell me how to do this. Below is ...
1
vote
1answer
650 views

Could not connect to host 127.0.0.1: Connection refused

Could not connect to host 127.0.0.1: Connection refused. - I am getting this error message on ktorrent on slackware 13.1 and the torrents cannot start. I tried to reconfigure the ktorrent prefernces, ...