a technological barrier designed to prevent unauthorized or unwanted communications between computer networks or hosts

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2
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59 views

How do I find which OS layer (iptables, rp_filter, etc) is dropping a packet?

Let's say that I'm running a ping towards a machine and I see from tcpdump that the icmp echo reply is being received at the ethernet port but the ping program is not getting it. So I know that ...
2
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2k views

Refused connection of ssh

I installed openssh on my new Ubuntu14.04 server, turned on ssh, and enjoyed it after I finished installation. Every thing was fine; however, after just one night, I was blocked when using putty as ...
2
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365 views

UFW is DENY/DENY, but PACKETS are still getting out of my ethernet device. Why is this?

Hello, I have a question. I would like to use the UFW Ubuntu Firewall to lock both Input and Output completely from the server to ensure no packets are sent initially as a baseline. I enabled UFW, ...
2
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0answers
138 views

found someone lurking in my LAN, not sure what to do next

I have DD WRT router with internal numbers all falling within 192.168.1.0/24. I was looking on my firewall records this morning and found someone at 10.10.109.100 got blocked from accessing port 5353 ...
2
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0answers
271 views

How do we allow a certain mac address in a FORWARD chain through iptables?

I set the iptables rules in default. # IPTABLES IN DEFAULT iptables -P INPUT ACCEPT iptables -P OUTPUT ACCEPT iptables -P FORWARD DROP How will allow a certain mac address in a forward chain? I ...
2
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990 views

IPTABLES > MAC Filtering

I am newbie. I tried DHCP Mac filtering is not enough to secure our networks and I think iptables will... This is my concept: I set a new laboratory (LAB) network. My other network is connected to a ...
2
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0answers
189 views

How should I configure Ubuntu firewall?

Just discovered Gufw, and I'd like to set it up. But I haven't found any documentation telling me what I should/should not allow. I'd like to be able to use it but the only documentation on the web ...
2
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596 views

How I can connect the syslog-ng with a mysql database?

Hi guys I want to use a syslog-ng server for logging data from the firewall and I get Data from the Firewall in the file /var/firewall.log but now I want that the logs go to a database. For this I ...
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0answers
261 views

Why is SSH not accessible after installing KDE on Ubuntu Server?

I installed KDE onto my Ubuntu server, which is operating as a file server. It installed a firewall that wasn't there previously. I can't reach any of the services I had operating on the box now, ...
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0answers
11 views

Ubuntu as a bandwidth throttling box on windows network

I need to test the performance of some applications over different capacity connections (broadband, EFM, LAN extension etc). How would i configure an Ubuntu server to sit between the main network ...
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0answers
19 views

Transparent proxy listening on sub-interfaces

I have iptables and squid on the same box. HTTP traffic doesn't seem to be going through the transparent proxy when I change my rules on the filter table. What is the best point to filter http ...
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33 views

How to know the all minimum privileges that software needs?

I am using a VPS as a public proxy, and I have begun to realize that I must make my VPS more secure as I have seen in Securing Public Shadowsocks Server. Shadowsocks is a fast tunnel proxy that helps ...
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0answers
41 views

Is this ufw configuration correct?

I have to link my openstack private cloud on a cloud management platform online. The cloud location is on my private ip (192.168.0.9) , i can't use that ip since the platform need a public ip so i ...
1
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0answers
71 views

How to config PORT KNOCKING on CSF ubuntu server and access it by linux?

I'm trying to run port knocking work on a CSF on a small VPS, i setup this: 1 - the result of csf first test ok 2 - TCP_IN = "53,80" TCP_OUT = "53,80,113,443" UDP_IN = "53" UDP_OUT = "53,113,123" ...
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0answers
166 views

Why is ip forwarding not working in xubuntu 14?

I upgraded my gateway computer from xubuntu 12 to 14 and the computers on my home network lost their internet connection. I found that the upgrade had uninstalled my old firewall, Firestarter, and ...
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0answers
2k views

UFW for OpenVPN

I want to configure ufw (uncomplicated firewall) for OpenVPN. Connections are only allowed through OpenVPN. Everything else should be blocked. So if OpenVPN is disconnected -> no internet! I found ...
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0answers
76 views

Can't Connect to Apache2 Server From External Device (in LAN) Nor From External IP?

I forwarded ports 80 and 443 for my apache 2 server. However, if I: try connecting to the server via external IP or try connecting to the server from a local device via my local ip, I cannot gain ...
1
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0answers
78 views

how to block all tcp and udp and other protocol and only allow layer 2 communication?

sudo ufw disable sudo ufw default deny sudo ufw allow XXXX sudo ufw enable Does sudo ufw disable block layer 2 by default? How to block all TCP, UDP and other protocols, so only layer 2 ...
1
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0answers
229 views

Why aren't these ufw rules working?

I'm trying to configure ufw to only allow connections to 3 ip addresses on my local network, and deny everything else. Here's the commands I'm using: yes | sudo ufw reset sudo ufw default deny sudo ...
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0answers
63 views

Ubuntu Randomly Rejecting Hosts

currently I am facing a very strange problem: my Ubuntu is randomly resetting connections and I have no clue why. /etc/hosts.deny is empty (resp. just the default file with comments only, that comes ...
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0answers
56 views

Connecting to Ubuntu host not possible

I have an Ubuntu-Host which is connected via wlan (and for testing to wired net) to a local net. This Ubuntu-Host is not reachable via network by any other clients on the same network. But: If I do a ...
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0answers
144 views

ufw is not working properly

I'm trying to enable ufw in remote ubuntu server. This server has two LXC container running. One container has nginx server running and I have hosted web application, right now every thing is working ...
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741 views

Ubuntu UFW init failure

I have some strange UFW behaviour. Whenever I install it cleanly and add some allowed ports to it (without restarting) it works great. But when I restart UFW or the whole server for the first time ...
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82 views

Dynamically Enable LAN traffic in Firewalld (using profiles in network-manager)

I am trying to use firewalld to allow dynamic profiles for different connections in Network Manager. When I'm at home, however, I would like to allow anything coming in on the LAN (local subnet). I ...
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0answers
88 views

Ubuntu server periodically unreachable

I have an Ubuntu Server 14.04 server running. The server has two NICs and acts as a NAT router, with the help of shorewall. Shorewall also acts as a plain firewall for blocking ports that I don't want ...
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172 views

Port forwarding out multiple VLAN interfaces that have same IP address

So I have an Ubuntu machine with multiple VLAN on an interface eth1 and each VLAN has the same IP address (172.16.0.2). I need to be able to simultaneously telnet into a rack of devices that are also ...
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0answers
71 views

Firewall rule to drop DOS attacks. What is wrong with my command?

I have a script like that : MAXREQ='cat /var/log/maxreq_tmp' DE=6 iptables -F iptables -I INPUT -p tcp -m state --state NEW -m recent --set iptables -I INPUT -p tcp -m state --state NEW -m recent ...
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0answers
97 views

Can't access Flask from local network

I've already read this thread, but it is not what I'm looking for. I'm running Flask on Ubuntu 13.10 with this configuration, but I can't access it from the local network using the correct ip and port ...
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0answers
7k views

ubuntu 14.04 default firewall rules

I would like to know exactly which scripts are responsible for default iptables rules (no ufw, no gufw) in Ubuntu Server 14.04. After fresh installation even with ufw disabled (by default) there are ...
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0answers
238 views

UFW, IPv6, and HTTPS

I'm running Kubuntu 13.10. I recently enabled IPv6, and setup UFW to support it. Everything seems to be working as expected, except I've noticed certain traffic being blocked with an AUDIT-INVALID ...
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0answers
153 views

Configuring ufw and iPredator VPN

I am running a VPN via IPredator on Ubuntu 12.04 Desktop, which works perfectly, when ufw is disabled. When I enable ufw, I logically cannot establish a connection. IPredator states that I have to ...
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89 views

Allow users to access specified IPs only

I have a computer that offers both a VPN and a SSH server running three (separated) VPN networks. All users log into the server via ssh. However, I want that only certain users can communicate to ...
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0answers
411 views

Squid proxy and firewall blocking HTTP requests

I have 3 virtual machines. One functions as a router. A HTTP server is installed on another machine. The third has to connect to the server via the router. I have installed a web proxy(Squid3) on the ...
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0answers
3k views

Ubuntu 12.04 LTS - vsftpd problem. No connection. Connection refused

i have a problem with vsftpd server running on Ubuntu 12.04 LTS. Here is the configuration: ubuntu Server address - 192.168.5.100 router address - 192.168.5.1 roger/# grep -v "#" /etc/vsftpd.conf ...
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0answers
63 views

Can a weak Ubuntu user password be a risk for ONLINE security?

Can anyone gain an unauthorized remote access to my Ubuntu machine? Does having a strong user password really helps prevent this? Or firewall just doesn't let anyone in by default, regardless of the ...
1
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0answers
1k views

SSH connections rejected after UFW allow 22

I am trying to setup UFW on a 12.04 server. SSH works great with UFW off. Setting root@ugvps:~# ufw enable Firewall is active and enabled on system startup root@ugvps:~# ufw status Status: active ...
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0answers
497 views

UFW Firewall Rules, has a hole in it. Please help

Can someone please look at the below output for me. I have my UFW on deny/deny, and here are the rules. But if I leave my Ubuntu Server on, with a Windows XP VM, and let Instant Messenger run in the ...
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0answers
351 views

New Server - apache will not serve outside LAN

New server, running well 12.04 LTS on HP ML350. Apache = great, inside our LAN. Apache = timeout, from WAN (NAT forwarded from firewall). I have cleared all Iptables, read & checked every ...
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0answers
102 views

Is there a firewall that blocks a process and shows a dialog with buttons Allow, Drop, Disable?

Currently I use ufw and Firestarter, and I'm just learning how to use a firewall. When I used windows there were a couple of firewalls that could block a process which tried to establish connection ...
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0answers
841 views

How to change Port 27000 from filtered to open status

In my ubuntu box I am running flexlm licensing software on port 27000 and I am able to pull the license from the this port to run the simulation software locally. I am also trying to run the same ...
1
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0answers
235 views

ssh client times out to some servers, works on others

I have a strange problem and I'm not sure where to begin. My ssh client works on some servers but times out on others. Obviously, I checked that the servers are accessible via ssh from other ...
0
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0answers
11 views

GUI Firewall status display

I'm looking for a panel item or screenlet or something to display the status of my firewall. /usr/bin/firewall-applet appears to be the right thing and it is already in "Startup Applications" ...but I ...
0
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0answers
11 views

iptables: write UDPv4: Operation not permitted (code=1)

I am trying to set up a stateful firewall using iptables. It is for use on my desktop machine. Below are the contents of my firewall script: #!/bin/bash iptables-save > ...
0
votes
0answers
11 views

OpenVPN disables DNS due to firewall

I'm trying to use an OpenVPN service with Network Manager. When I'm on wireless and activate the VPN, it works flawlessly, but when I'm on a wired connection, I have no Internet access. Through trial ...
0
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0answers
6 views

Subdomains Stopped Working after APF Firewall Install

I've just installed APF Firewall to my Ubuntu 12.04 server. Everything went fine and www.threecreative.co.uk is displaying okay, but none of my subdomains appear to be working. Any thoughts? For now, ...
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30 views

What is Network-manager trying to do with rdisc?

I have quite strict firewall setup using (g)ufw, allowing only some known to be useful outgoing traffic and denying the rest. I have noticed these recurring messages in syslog, and I'm wondering what ...
0
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0answers
42 views

remote CORBA lookup (firewall, port, telnet)

I'm trying to do a CORBA lookup on a LAN from one pc to another. How do I troubleshoot the connection? On the server running glassfish: thufir@doge:~$ thufir@doge:~$ ...
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0answers
47 views

error: Idle Subprocess didn't make a connection. Either Idle can't start a subprocess or personal firewall software is blocking the connection

When i run idle it returns the above stated error. It happened after I installed python 3.4. both 2.7 and 3.4 are giving this error.
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0answers
23 views

Iptables: some ports are closed despite being open by my iptables; can it be something else?

Beginner question. I set up the following iptables rules: #!/bin/sh # Réinitialise les règles sudo iptables -t filter -F sudo iptables -t filter -X # Bloque tout le trafic sudo iptables -t ...
0
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0answers
39 views

Firewall Config to get access to ports via eth0

My headless ubuntu Server has an OpenVPN client that connects to a gateway provided by PIA. I gathered some settings provided here to basically setup kill switch I have a domain that redirects to ...