1
vote
0answers
29 views

How to debug the network issue in case of blocked database connections

I am trying to understand if my analysis of the below information is correct. For all the 3 scenarios listed here, port 80, port 3306 and port 22 are open in the server's firewall. Also, for all the 3 ...
1
vote
0answers
48 views

How do I control ip routing in the new firewalld?

I have the following scenario: Our fedora server is connected to the internet on eth0 and has a second nic, wlan0 acting as an access point. The purpose of the access point is to provide a connection ...
1
vote
0answers
91 views

iptables server behind NAT accessible from outside as well as inside the nat

I have 2 machines with a KVM running on each machine - so two kvms with the below networking Host 1: 192.168.10.100 (eth2) 10.10.100.1 (virbr1) KVM 1 (NAT with Host 1): 10.10.100.128 (eth0 ...
0
votes
0answers
103 views

What is wrong with these iptables' rules?

The following is what I got after googling: iptables -A INPUT -i lo -j ACCEPT iptables -A OUTPUT -o lo -j ACCEPT #allow loopback access iptables -A OUTPUT -d 255.255.255.255 -j ACCEPT #make sure you ...
4
votes
1answer
293 views

bridge does not forwarding packets centos

I am using CentOS 6.5 64 and use xen to create a virtual machine (CentOS) ifconfig [root@CentOS ~]# ifconfig eth0 Link encap:Ethernet HWaddr 08:00:27:54:B3:FA inet6 addr: ...
1
vote
1answer
139 views

Does an in-kernel firewall sit between the network access layer and Internet layer?

This question is a follow-up to my previous question. Logic for me to says that an in-kernel firewall sits between the network access layer and the Internet layer, because it needs to have access to ...
0
votes
1answer
50 views

What does the last column in this IP table mean?

From a tutorial, I run $sudo iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT $ sudo iptables -L and get target prot opt source destination ACCEPT ...
3
votes
1answer
51 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
1answer
265 views

iptables couldn't load target allow

I am using the command below to allow all traffic from hosts on my internal network but it says "iptables v1.4.18: Couldn't load target `ALLOW':No such file or directory". What is the problem here? ...
0
votes
1answer
154 views

iptables - why the stun, turn ports are not working to allow end points to access the server?

I have this iptables where all working except tcp/udp port 3478 and 5349. $ cat /etc/sysconfig/iptables # Generated by iptables-save v1.4.7 on Thu Nov 21 10:21:41 2013 *filter :FORWARD ACCEPT [0:0] ...
2
votes
1answer
31 views

Ubuntu blocks access to services when not logged in

I'm not really sure what's going on here. I have the following: A fresh install of Ubuntu 12.04 LTS. Jira 6.1.2 installed as per instructions from Atlassian. Confluence 3.5.13 installed as per ...
1
vote
2answers
192 views

How does KVM set its own netfilter rules?

I've been poking around with KVM VM's on Centos 6.4 and after some hair pulling and copious amounts of trying to break my desk with my head due to not having an internet connection on my VM's, I found ...
1
vote
2answers
196 views

Open a port CentOS

I'm new in CentOS and I'm trying to create a little script in Python, something like: $ python -m SimpleHTTPServer If I try to access port 8000 in my web browser, I don't get access, however if I ...
2
votes
1answer
106 views

Linux GUI to track connections made from/to this computer

Is there a GUI to track any socket connection sent to this computer and which program that initiates it? Also if possible track any incoming connection sent to this computer and which program that ...
0
votes
1answer
77 views

Is there any tools which can be used to make ports available from any firewall network?

I have been testing my application which has TCP/UDP ports for peer to peer with the help of server signalling commands for making communication, that works when I have Public IP or Lan IP and not ...
2
votes
1answer
55 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
937 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) +-----------+ | ...
1
vote
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
votes
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
vote
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.. ...
1
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
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
323 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 ...
39
votes
4answers
23k 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
703 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 ...
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 ...
0
votes
1answer
972 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 ...
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
157 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 ...
8
votes
4answers
735 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
734 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 ...
11
votes
4answers
2k views

Why do we need a firewall if no programs are running on your ports?

When I try to telnet to a port on a server, and if there is no program listening on that port telnet dies with a "Unable to connect ... " error. I understand that. But, why do we need a firewall if ...
4
votes
2answers
346 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 ...
5
votes
4answers
1k views

How can I send spoofed packets in Linux

In order to test a firewall, I want to send malformed packets to its interface, regardless of my routing table. Is there a way to ask linux "send this exact tcp package, to this MAC address, ...
6
votes
2answers
573 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 ...
6
votes
3answers
370 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
vote
1answer
482 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 ...