A networking program that controls the incoming and outcoming stream of data in a computer.

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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 ...
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vote
1answer
188 views

Possible sftp connection behind a router that is impossible to open any public ports except some standart ports like http?

I want to ask about the problem that I have with my office computer. I cannot reach the router so I cannot redirect any incoming requests to my PC. I have to get a huge file from another computer on ...
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0answers
52 views

Firewalld SELinux

Is there any way to better explanation firewall-cmd than the one given in Fedora18 wiki. I am trying to convert iptables to FirewallD in cmd line without GUI but cannot find a decent example or ...
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0answers
156 views

PGP keyserver and proxy firewall issues

I am not sure this is a Linux question directly ... I use Arch Linux which uses package signing. This requires me to download a set of pgp keys with the pacman-key program. This works off the ...
7
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4answers
13k views

How to check whether firewall opened for a port but not listening on the port

We will be deploying a new application to a Server and the application will be listening on port 8443. We have asked Network team to open the firewall for the port 8443 on that server before deploying ...
1
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1answer
100 views

Adblock rule to block g+ / twitter / etc. [closed]

Looks like this rule works to blocking facebook domain, when not visiting the facebook domain (ex.: "like/share" etc. buttons on other pages then facebook): ! don't allow facebook outside facebook.. ...
5
votes
4answers
4k views

iptables rules not reloading on CentOS 6.x

I have one single ipset added to my iptables on a CentOS 6.x box and this rule is lost when the machine reboots. I've found this answer showing how to make a Ubuntu system reload the iptables rules ...
2
votes
1answer
518 views

How can I disable UFW logging for a specific event?

My router sends out multicast packets in regular intervals that are blocked by UFW's standard policies. These events are harmless but spam my syslogs and ufwlogs. I can't change the router's behaviour ...
3
votes
3answers
571 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 ...
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vote
3answers
242 views

Packet analyzer to intercept and filter incoming traffic before any client app

I am curious if most Linux distros make it possible to intercept incoming network traffic as soon as it enters the system and filter its content based on some rules before any other client can use it ...
2
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0answers
225 views

Port Forwarding Between 2 Internet Machines

Here's my scenario: Setup There are 3 machines: A: on the internet : has ip (a.a.a.a), has port pa open B: my server / gateway : has ip (b.b.b.b), has port pb open C: on the internet : has ip ...
3
votes
2answers
352 views

Is it possible to whitelist a specific program in iptables?

Is it possible to allow all traffic for a specific program in iptables? Otherwise using nmap and a strict iptables configuration at the same time seems impossible.
0
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1answer
24 views

EST/REL or REL/EST in iptables firewall scripts?

-A INPUT -p tcp -m state --state RELATED,ESTABLISHED -j ACCEPT every Firewall rule usually starts with this. Q: Does it matter that is it RELATED,ESTABLISHED OR ESTABLISHED,RELATED?
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votes
3answers
1k views

What does this firewall record mean?

Running iptables -L -n gives me the following info: Chain IN_ZONE_work_allow (1 references) target prot opt source destination ACCEPT tcp -- 0.0.0.0/0 ...
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vote
1answer
177 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. ...
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1answer
847 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 ...
3
votes
1answer
191 views

IPFW Port Forwarding

This is my situation: I want to connect to an OpenVPN server from my office (we're using a proxy, only ports 80 and 443 are allowed). Server IP address is: 176.31.250.232:843 My static IP address ...
3
votes
1answer
4k views

How to re-enable iptables on Fedora 18?

FirewallD is the default firewall in Fedora 18. I have been using iptables for quite some time and have a custom configuration which I need for logging of ip traffic. I am not used to the new ...
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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 ...
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2answers
139 views

Fedora Firewall no option as of yet

I need a firewall because I was decade long user of internet security suites on windows. I am not a professional of networks or anything but a student who just needs to block unblock running ...
2
votes
1answer
1k views

What to use for firewall testing (port opened or not)

so... we know that we can test that if a port is open on the firewall with: telnet SERVERIP PORT ..but afaik there are services that can't be tested with telnet, because ex.: telnet doesn't know ...
2
votes
1answer
230 views

How to configure OpenBSD pf to only allow inbound from given countries?

I have an OpenBSD 5.2 box what's running a webserver on port 80 and an SSHD server on port 2222. How can I configure OpenBSD's pf to only allow connections from given countries to port 80 and 2222?
2
votes
1answer
294 views

How to interpret and react to Shorewall log?

I see the following pattern in every 2-3 sec, for several minutes in syslog: Shorewall:net2fw:DROP:IN=eth0 OUT= MAC=aa:bb:cc:dd:ee:ff:gg:hh:ii:jj:kk:ll:mm:nn SRC=12.34.56.78 DST=98.76.54.32 LEN=60 ...
3
votes
1answer
317 views

Can I limit connections per second for certain UserAgents using UFW?

GoogleBot is hitting my server hard - and even though I have set the CrawlRate in Webmaster Tools it is still hiking up the load on my server and slowing down Apache for the rest of the normal web ...
4
votes
1answer
3k 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 ...
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1answer
300 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 ...
0
votes
1answer
570 views

Allow incoming connections from Google Translate only

I have a small web server running on port 80, and I'd like to allow only Google Translate to have access to it. First I tried running dig translate.google.com and dig translate.googleusercontent.com ...
3
votes
3answers
720 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
2k views

nmap shows me that one service is “open|filtered” while locally it's “open”, how to open?

I have a Quake 3 server. And it's launched successfully. The problem is that no one can connect to that server. I am running: nmap -sU -p 27960 hostname and it's showing me that it's state ...
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3answers
10k views

How to block https facebook site using iptables [duplicate]

Possible Duplicate: iptables to block https websites I am using Zentyal Os as a firewall, it working fine like blocking http sites and but I am not able to block https facebook site. My ...
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0answers
126 views

Perform Cisco's DNS Doctoring on FreeBSD

How to perform a change in the DNS response from a DNS server to be a different IP address than the DNS server actually answered for a given name? ...
3
votes
3answers
2k views

MySQL Linux Client Timeout/Keepalive

Is there a way to set a keepalive in the command-line MySQL client on Linux? Our network recently moved to a VLAN setup, and our systems department no longer has control of the firewall. The ...
5
votes
1answer
2k views

Enable RTSP in iptables

I'd like to receive a RTSP stream via VLC, but when I try to run sudo -u non_root_user cvlc -vvv -I dummy rtsp://ip:port/x.sdp I get: Unable to determine our source address: This computer has an ...
2
votes
1answer
322 views

Make box only communicate on lan only?

I am running a VM with Debian as the guest OS (I can choose another distro). It has nginx running along with some other software. Some of the software tries to make outgoing connections (for example ...
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0answers
134 views

What other rules should I use to allow PPTP outbound connection?

I already allowed outbound connection to TCP/UDP port number 1723, but PPTP connection still fail to establish, If I allow all outbound connection, the tunnel will just go fine.
4
votes
1answer
589 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 ...
2
votes
1answer
717 views

Changing firewall settings after installation of CentOS via kickstart

I was trying to install CentOS 6.3 via Windows Deployment Server. And to automate the installation process I used kickstart file in which i provided various details required during installation.Then i ...
39
votes
4answers
22k views

How does reverse SSH tunneling work?

As I understand this, firewalls (assuming default settings) deny all incoming traffic that has no prior corresponding outgoing traffic. Based on Reversing an ssh connection and SSH Tunneling Made ...
4
votes
1answer
3k views

How to configure pfsense to NAT servers?

How can I configure pfsense so it will NAT servers so they can be accessed outside of the company? I tried to play around with the NAT settings, but didn't get anywhere. I want to be able to access ...
4
votes
2answers
702 views

NAT and source IP filtering in PF, using OpenBSD >= 4.7

I just read a book about PF (The Book Of PF, No Starch), but there's one question not answered by it. If I have a gateway machine using two interfaces, $int_if and $ext_if, and I NAT the packages ...
6
votes
3answers
7k 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
2k 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 ...
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vote
1answer
2k 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 ...
3
votes
2answers
785 views

How to Add rules to IP Filter (Firewall in SCO)

I need to add a rule (allow any to any port 22) to my firewall, so that I can ssh remotely into my machine. I have had a look in the SCO OSR600 Documentation and I cannot find anything in there that ...
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2answers
1k views

How to allow mysql remote connections via particular interface

I have a 10.237.49.251 IP on eth0 and another IP on another interface How do I enable remote mysql calls on eth0 device?
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2answers
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What is a solid iptables configuration for my desktop?

On my desktop, I want to configure iptables pretty strictly. I see no reason why I need to allow anything except for internet traffic that I initiated. And maybe even that could be limited to only a ...
0
votes
1answer
968 views

Network Printing in Fedora

I´m having problems setting up network printing in Fedora 16. In the printer setup box it says FirewallD is not running and gives a list of protocols that need to be enabled. I cannot find a FirewallD ...
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 ...