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

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How to open the ports on firewall in Ubuntu? [duplicate]

I'm pretty new to Ubuntu. I just want to open the most common ports namely FTP (port 20 TCP/UDP) HTTP (port 80 TCP/UDP) SMTP (port 25 TCP) ETC I've tried all the ways in iptables, ufw, and gufw. ...
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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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60 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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3answers
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14.04 missing “/etc/init.d/ufw”? my firewall never auto starts

I need to know how to fix the missing "/etc/init.d/ufw" file, is it some package or some command? I used the gufw to enable it, but on reboot my firewall was still off... I created a symlink ...
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1answer
730 views

Ubuntu 14.04 denying incoming access

I just install a Counter-Strike: Source Dedicated Server on my Ubuntu 14.04 Desktop amd64 and I'm having trouble to allow incoming access to this server from the internet. I did a port forwarding on ...
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1answer
2k views

Iptables rules no longer honored

I installed Ubuntu Server 64-bit 14.04 a week ago. It worked fine for one to several days, then out of the blue, iptables became meaningless (I noticed FTP and such are down ). Only ports 22, 25 & ...
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2answers
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What is MASQUERADE in the context of iptables?

In Iptables many times I see the target MASQUERADE. What is that. I searched and find lots of things. But I need some one explain me what MASQUERADE is in a so easy way? **If you bring an example ...
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0answers
218 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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947 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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353 views

configuration for ufw to allow upnp between desktop and xbox360

I am really stuck with this question. I am using Ubuntu 14.04 I cannot enable UFW to allow a connection between my desktop and Xbox 360 stream media when UFW is enbaled. The connection and streaming ...
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1answer
2k views

Firewall rules for transmission

I have transmission installed, which listens on the default port 51413. I have tried opening everything for this port. iptables: Chain INPUT (policy ACCEPT) target prot opt source ...
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89 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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103 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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1answer
69 views

iptables ruleset blocking all network activity?

I've gone through numerous trial and error to recently discover that my iptables result is the culprit of blocking all LAN and WAN activity. I know this, because if I comment out the last line in my ...
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1answer
321 views

Docker is blocked by UFW

I have problem with Docker network in ubuntu 14.04. I have installed Docker.io from official repo and I've added DEFAULT_FORWARD_POLICY="ACCEPT" to /etc/default/ufw but my Docker containers still ...
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1answer
2k views

Where to get nftables?

As far as I understand the kernel facility nftables exists in the kernel that comes with Ubuntu 14.04. As is proven by the following two commands: # grep -E '(NF_TABLES|NFT_)' /boot/config-$(uname ...
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194 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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87 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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2answers
853 views

UFW rules don't work with docker

I have a 12.04.4 server, and I have enabled ufw, and have tried to block port 8080. However, it is still open. $ sudo ufw deny 8080 Rule added Rule added (v6) $ sudo ufw status numbered Status: ...
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1answer
66 views

Connection timed out on specific ports

We have an apache server running couchdb on port 5985 (not 5984). On my computer, I have Windows 7 and Ubuntu 14 LTS. From Ubuntu, I can connect to the host via http://example.server.domain, but I ...
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8k 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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2answers
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How do I with ufw deny all outgoing ports excepting the ones I need?

I did the following: ufw default deny outgoing, sudo ufw allow out 80 which I thought would let me use the Internet but didn't can y'all help? Also are there any other ports used by Ubuntu for which ...
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1answer
141 views

Juju security model issues

What plans are there to extend the security model in Juju? We see two significant issues with the current model - no internal firewalling within an environment, and the inability to expose ports to ...
2
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1answer
407 views

ufw firewall disabled - How to turn it back on?

I am using Ubuntu 12.04 and just recently noticed, that my ufw-firewall is turned [off]. I know It's turned [off] by default, but when I set Ubuntu up, I turned [on] the firewall with: sudo ufw, but ...
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1answer
814 views

basic security tools and packages that should be installed on a public facing web server

I'm a newbie in this world and I do not have a lot of knowledge about how security works on Linux systems. I recently created a droplet on DigitalOcean with Ubuntu 13 and I've been setting it up by ...
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1answer
487 views

Ubuntu forward ports, default state, forwarding not working?

im running ubuntu 12.04.4 server. I been googling the nett for answers, but could not find any.. I would like accsess a few web-gui's on my server. I have forwarder the ports in my router, worked when ...
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2answers
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Problem with ufw enable: libkmod: ERROR ../libkmod/libkmod.c

I am trying to enable ufw and this is the output: root@p:~# ufw enable Command may disrupt existing ssh connections. Proceed with operation (y|n)? y ERROR: problem running ufw-init libkmod: ERROR ...
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1answer
638 views

Iptables and bind9 to forward to google's dns

Hello i have a very hard time on getting along with iptables and bind9 as my internal network dns server. It's configured to forward my queries to google's dns (8.8.8.8). The main problem is i can't ...
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2answers
224 views

Why does DEFAULT INCOMING DENY not stop Firefox from working?

If UFW is actually not an application layer firewall but a "interface to iptables", how can it be if I have by DEFAULT INCOMING DENY and OUTGOING ALLOW setting that ANY internet application is ...
2
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1answer
263 views

Need help to make this file work in iptables

I came across the following example of how to use iptables to block internet access when the VPN connection is terminated abruptly: iptables -A INPUT -i lo -j ACCEPT iptables -A OUTPUT -o lo -j ...
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1answer
756 views

Server unexpectedly closed

So I know that similar veins to this topic have been posted, but mine specifically deals with the fact that my SSH login through Putty worked from my desktop and my laptop. However, after carrying ...
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3answers
986 views

apt-get does not work without an internet connection. How can work around this?

I have a host which is firewalled to the point where apt-get is unable to download packages. That host does not have access to a proxy. I know in gentoo I could work around the problem by fetching ...
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1answer
204 views

enable port 9696 on ubuntu server

I am using ubuntu server lts 12.04 on vmware virtual machine. I need to enable port 9696 which is blocked or filtered. When i use the nc -v -w 1 localhost -z 9696 command it shows me the following ...
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3answers
736 views

using nmap for information regarding web host

am trying to get info of host run in linux about open/closed port the host is attacked randomly by hackers changing the content of the page.deleting files,homepage content changed. how can it be ...
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0answers
69 views

Port won't open! [duplicate]

I have a server that want to allow connections into it through port 25565, but when I test on http://www.yougetsignal.com/tools/open-ports/ it says they are closed? I have no outfacing interface ...
7
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1answer
369 views

Why are certain things able to get through ufw firewall?

I should say up-front that I am TOTALLY new to Linux, Ubuntu, and the technical side of networking. I am setting up Ubuntu on a server computer and have learned a bit about configuring the ufw ...
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0answers
398 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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1answer
158 views

Setting up Ubuntu server with firewall - do I need 2 NICs?

Assume a LAN where 4 port ADSL Router, Server and PCs all connect to a network switch. Apart from working with the server, the workstations must have restricted access on what sites they can use. For ...
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2answers
178 views

Where did I fail with my basic iptables setup?

I installed iptables on a VPS (Virtual Private Server from openVZ) - Linux 2.6.32-24-pve #1 SMP Fri Sep 13 07:29:30 CEST 2013 i686 GNU/Linux. I also installed: apt-get install iptables-persistent ...
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1answer
336 views

UFW locks me out of server everytime I run it

Background: I'm setting up a new 12.04 instance on a VPS with a new provider.The VPS provider only offers a 32bit image but that really shouldn't matter here. I have no local access to the machine and ...
2
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1answer
270 views

Can't Get UFW Firewall to Allow Anything

I'm trying to set UFW (using GUFW) to create a firewall that only allows network connections when OpenVPN is connected. So in GUFW I deny incoming and outgoing connections and enable the Firewall. I ...
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2answers
1k views

SSH tunneling over SSL

On one of my systems there is a firewall forbidding any outgoing unless http(s)... Some users have to ssh but they can't.I tried first to run ssh on port 443 but with no success. I googled it and ...
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1answer
51 views

Setting up a basic firewall for 1st time user

Could anyone tell me some basic commands to set up my firewall. I already have ufw. What commands should I use for a basic security?
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1answer
199 views

why Ubuntu Firewall not showing verbose?

Even Ubuntu Firewall in running mode , I am not getting the data. may I know why ? root@ubuntu:~# sudo ufw status numbered Status: inactive root@ubuntu:~# service ufw start start: Job is already ...
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2answers
1k views

UFW not blocking connections to docker instance

I have a webservice running inside a docker instance which was run using the following command: sudo docker run -d -p 4040:4040 .... My UFW rules look like this: ~ sudo ufw status Status: active ...
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111 views

Firewall Activation Process

How do I activate my firewall through the terminal and is it Necessary or done automatic. My regards team! thmoabw
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278 views

open ports in ubuntu 13.10

Ubuntu comes with no open ports. Mine is a fresh install with only skype xbmc and wine added. I installed GUFW and set it to ON. When I do sudo netstat -tulpn | grep LISTEN I got: tcp 0 0 ...
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173 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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1answer
73 views

Samba problem — is it a firewall issue?

I have just installed Ubuntu 13.10 on a computer I use as archive for other machines. I need Samba working from various Windows 7 machines. I have confirmed that smbd and nmbd are both working, and ...
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4answers
5k views

How to deny an ip address from connecting to my system?

Is there a way to deny an IP address from connecting to my Pc? Is there a way to deny an Ip from connecting to specific Port?