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

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2
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0answers
106 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 ...
0
votes
1answer
315 views

network bridge not forwarding traffic from span port on router

I want to run several security network tools in LXC containers like ntopng, suricata, snort, etc. I hooked one of my server's NIC's up to a port that is spanned to my firewall... so basically this ...
0
votes
1answer
54 views

I have some questions about Firewall [closed]

So I am pretty new to Linux (With the exception of Android), and being use to the old ways of Windows pretty much all I had to do for Firewall was turn it on and forget about it. However with Ubuntu ...
0
votes
1answer
244 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 ...
1
vote
1answer
150 views

How can I tease Sonicwall?

In my college, I can't use the web, because they use Sonicwall network firewalls How can I tease it? For I use all websites in my college? Please see the result when I access a website blocked ...
1
vote
0answers
92 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 ...
0
votes
1answer
610 views

Setting up an Ubuntu Server 14.04 Firewall. Can it Protect multiple pc's on a local network?

I am new to Ubuntu firewalls. I would like to setup an Ubuntu Firewall on computer #1 it can be connected wirelessly or by Ethernet. I have another ubuntu server running on computer #2 and windows 7 ...
0
votes
2answers
212 views

How to block parts of a website

I already use the hosts file to get rid of entire domains that are time sinks, but some websites that largely are wastes of time (eg reddit) have useful parts. So I'd like to allow ...
0
votes
1answer
2k views

what could be blocking port 5060 on my ubuntu 14.04?

I have a ubuntu 14.10, and am trying to telnet into it via port 5060 but I keep failing. I always get the message "Connection closed by foreign host". I checked my iptable, it is default policy to ...
0
votes
1answer
259 views

Skype has stopped working on Ubuntu Studio 14.04.1

This is what Skype displays when I try to connect. I've tried reinstalling, but still no fix. When I sign in on my mobile phone it works, so I know it's an issue affecting only the desktop version.
0
votes
3answers
2k views

The program 'iptables' is currently not installed

I am a newbie, so my apologies up front. I am trying to get DansGuardian installed (which I believe I have) and working. To get it working I need to filter IP traffic through the app via iptables. ...
2
votes
0answers
3k 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 ...
14
votes
6answers
4k views

Does spyware exist for ubuntu?

Someone I know said he had put spyware on my computer. Is he talking crap? I've been using Ubuntu 12.04 for nearly 3 years now and I've never seen any type of spyware, remote keyloggers or RATS ...
0
votes
2answers
814 views

find mac address of all connected systems [duplicate]

How can I find out how many system are connected to the local network and how can I get all IP and mac address of these systems. Is their any command/package to show the IP details? Can I use this ...
1
vote
0answers
107 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 ...
0
votes
1answer
140 views

Differences between UFW and GUFW

From what I have been able to piece together, the firewall that comes with Ubuntu is iptables, which is very complicated, so an easier way to access the firewall is through UFW and GUFW. UFW is ...
1
vote
0answers
336 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 ...
1
vote
2answers
944 views

How do you view all of the banned IP's for Ubuntu 12.04 via the command line?

I can't seem to find a quick command to just view all the banned IP's on the server. Or is there a file I can just edit? I'm guessing fail2ban is the one that inputs all the IP's to ban. Where do I ...
1
vote
1answer
973 views

What are the IP addresses in my iptables chain FORWARD settings in a Dokku/docker setup?

I've been playing around with Dokku on DigitalOcean (following this guide) and I'm trying to understand current firewall settings. So here's my setup: Ubuntu 14.04 Dokku Docker (as part of Dokku) ...
0
votes
1answer
117 views

keep getting added to hosts.deny + iptables

I am confused to why this has started to happen. On my local network, if I click 10-20 apache/http links my server will decide to add me hosts.deny file and block me on iptables. Its not just ...
0
votes
1answer
1k views

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. ...
1
vote
0answers
89 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 ...
1
vote
0answers
62 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 ...
3
votes
3answers
2k views

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 ...
0
votes
1answer
795 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 ...
4
votes
1answer
3k 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 & ...
7
votes
2answers
3k views

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 ...
1
vote
0answers
266 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 ...
1
vote
0answers
1k 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 ...
0
votes
1answer
387 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 ...
1
vote
1answer
3k 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 ...
1
vote
0answers
99 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 ...
1
vote
0answers
113 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 ...
0
votes
1answer
73 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 ...
4
votes
1answer
351 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 ...
2
votes
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 ...
1
vote
0answers
220 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 ...
1
vote
0answers
104 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 ...
6
votes
2answers
898 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: ...
0
votes
1answer
72 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 ...
1
vote
0answers
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 ...
0
votes
2answers
2k views

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 ...
3
votes
1answer
157 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
votes
1answer
464 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 ...
4
votes
1answer
982 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 ...
0
votes
1answer
666 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 ...
1
vote
2answers
1k views

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 ...
0
votes
1answer
660 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 ...
2
votes
2answers
233 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
votes
1answer
285 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 ...