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

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20 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 ...
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75 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 ...
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197 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, ...
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126 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 ...
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154 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 ...
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871 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 ...
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171 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 ...
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521 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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250 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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30 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 ...
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36 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 ...
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88 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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40 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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37 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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313 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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55 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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53 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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110 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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46 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
52 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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5k 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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50 views

Cannot connect to work VPN

I'm using Ubuntu Studio 13.04 Saucy, and generally new to Ubuntu. I work for a company which provides Windows based pptp VPN access for working remotely. Soon after I installed Ubuntu Studio, I was ...
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186 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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101 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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82 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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317 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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2k 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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146 views

ubuntu server apf-firewall configuration

I have not used the apf-firewall before and I'm having trouble configuring it. I have already try setting the iptables but it fails to start, so what more do I need to do? thank you
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60 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 ...
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846 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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375 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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243 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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69 views

Can not permanently clear iptable rules

I use the following commands to flush all iptable rules: sudo iptables -F sudo iptables -X sudo iptables -t nat -F sudo iptables -t nat -X sudo iptables -t mangle -F sudo iptables -t mangle -X sudo ...
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0answers
95 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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69 views

How to load firewall before network?

How can I ensure iptables gets up before any network adapter gets up? And can network be stopped to be brought up if there is an error in the firewall rules? For exiting and future network adapters. ...
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645 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 ...
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176 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 ...
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0answers
503 views

Firewall stopped and disabled on system startup ERROR: problem running ufw-init

I am trying to set a VPN server on my PC (Ubuntu). I am following a tutorial , http://cviorel.easyblog.ro/2009/02/09/how-to-set-up-a-vpn-server-on-ubuntu/. I made changes in various files including ...
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10 views

Ubuntu Server 14.04: Configuring ConfigServer Security & Firewall for Mediatomb

I am currently have issues with getting Mediatomb to work with CSF on my home network server. I have been able to get the Mediatomb server to work with CSF turned off. My Mediatomb web GUI is set to ...
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0answers
31 views

Shows :::18332 instead of 0.0.0.0:8332, what means that?

What means ::: in front of a port (where usually the IP should be) when doing netstat? It shows :::18332 instead of 0.0.0.0:18332 and I can't connect to that port from the outside. This is for ...
0
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0answers
10 views

webstorm website connecting remotely

I am new to Ubuntu and to webstorm so please bare with me if its very basic question. I am trying to connect to the website run by webstorm on Ubuntu from Windows 8.1 PC ...
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24 views

UFW behind a router blocks traffic from the outside world

I'm seeing [UFW BLOCK] entries in my logs, where SRC=173.194.67.16 DST=192.168.1.2. My box is behind a router, DST is my internal IP, SRC seems to some Google server and I don't understand how is it ...
0
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0answers
40 views

vino-server: local connection works but not remote connection

I would like to remotely take control over ma grandma's PC, where I installed lubundu 14.04.1. This is not a duplicate of this other question (I want to avoid teamviewer + see below). I configured ...
0
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0answers
35 views

Processes in docker cannot connect with ufw enabled

I'm trying to setup a server to use ufw with docker (via dokku.) When ufw is enabled, I cannot open connections from one container to another. When it's disabled, I can connect fine. As an example, I ...
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26 views

Has Ubuntu some firewall activated by default?

Because I can't seem to connect to my ip-cam. And mnap produces alternating results if I use the cams IP address: Nmap scan report for 192.0.0.64 Host is up (0.00079s latency). Not shown: 991 closed ...
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93 views

Port 80 apparently closed ubuntu 14.04

I'm installing a small server on the company where I work. I go to whatsmyip.org and it tells me it is 190.124.165.35. When I go to canyouseeme.org it tells me that the connection timed out for port ...
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77 views

captive portal and squid3 transparent mode

http://aryo.info/labs/captive-portal-using-php-and-iptables.html I did at practice. but squid (transparent mode should be) entered in the access.log s pages can not see. I use the following iptables ...
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38 views

ipset with iptables-persistent

iptables-persistent was not reloading my rules at restart, and I realized the problem was that /etc/iptables/rules.v4 contained a --match-set referring to a set of rules created by ipset - which had ...
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0answers
27 views

Ethernet connection blocks some traffic while wifi works flawlessly

I'm not sure whether it's related, but I recently tried to reroute inbound traffic from a user-accessible port to port 80 following these instructions: http://serverfault.com/a/112798 Now, I can't ...
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0answers
14 views

Allowing web site through shorewall firewall

I'm fairly new to Linux and I've been following some guides to get a web server up and running. So far all is well with the web server and accessing it from the net. I've installed Shorewall firewall ...