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

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Foraward Traffic from local machine to proxy server using iptables

I am using Ubuntu Server 12.04. My IP is 192.168.4.160. I want to route the HTTP traffic generated locally from my system destined to a particular URL (say x.x.x.x) to pass through proxy server. My ...
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250 views

UFW blocking random packets on 443

All, I have UFW setup to allow traffic on port 443. It works as expected, though I have a large amount of UFW Block log entries. To Action From -- ...
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38 views

Too Many unsolicited “Incoming Connections”

With the ufw rule "deny incoming", ufw logs as many as 2 to 3 block packets from random IPs on random ports. I find it quite irritating. I was just wondering if this is normal "midirected" internet ...
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1answer
1k views

Can't delete an iptables chain

I'm having a problem on deleting a user-defined chain. these the are rules I entered. sudo iptables -t mangle -N internet sudo iptables -t mangle -A PREROUTING -i eth1 -p tcp -m tcp --dport 80 -j ...
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1answer
65 views

after software update, website not accessible

I just applied a bunch of recommended updates this morning (which seems to have upgraded the kernel to 3.8.0-32.47), and suddenly I cannot connect to the machine on port 80 (http) or 22 (ssh). Ping ...
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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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67 views

Beginner Help Configuring Iptables

I have just started to configure iptables and I am wondering what basic rules you would recommend that I use for the things that I need. Here is what I am doing: I want my default policies for ...
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167 views

I have UFW block messages from local network machines, how can I analyse if they are malicious?

I'm getting a lot of messages in my UFW log, and I'm trying to figure out if these are malicious or just normal. A UDP broadcast is coming from a windows laptop x.x.x.191, and some from our synology ...
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129 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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150 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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1answer
1k views

Ban IP by country in UFW

I want to block a country in my server, but I don't know which rule I must use in UFW (or iptables). For example, people from US and other countries can see the site, but visitors from Russia can't. ...
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1answer
526 views

UFW, allow from wlan to eth

I would like to use my ubuntu 12.04 notebook as a wifi hotsport to my smatphone. Everything is going ok, using dnsmasq and hostapd and allowing ports 68 and 53 on UFW. But to access the web the UFW ...
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1answer
547 views

What's the difference between -p tcp and -m tcp in iptables?

I just noticed an entry in /etc/sysconfig/iptables along the lines of -A INPUT -p tcp -m tcp --dport 138 -j DROP I am not so sure why there has to be two switches here for matching protocol TCP, ...
2
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1answer
7k views

How can I allow ssh connection from an IP subnet on port 10022 using iptables?

I need to set up a server with public IP for bandwidth testing, and I already have a script to drop all incoming traffic except for the ports I need. I have changed the ssh port from default (22) to ...
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2answers
1k views

Ubuntu - apt-get not working behind restricted internet access

I have Ubuntu 12.04 64-bit boxes running in a company but they have internet browsing and firewalls for security. When I do apt-get update or install it fails. But I have a remote server which ip is ...
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1answer
93 views

No matter what I researched and did I can't connect to my MySQL server

Ubuntu installed MySQL for me through LAMP. When I connect with SSH I can login with the root user but not the user i created myself. When I use HeidiSQL I can't login with anything. I ran these ...
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1answer
336 views

Understanding Iptables

iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 7000:7010 -j ACCEPT I trying to understand the -m state --state NEW part. Searching through the man pages and correct me if I am wrong ...
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61 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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6answers
1k views

Do I need a firewall for my desktop?

I don't have a router, but I mostly use my desktop for online shopping and torrenting. So, do I have to enable the firewall? I hope not, because I'm really dumb and I don't think I will be able to ...
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1answer
611 views

Ubuntu Firewall: Apache only visible on lan

How can I add a rule to the Ubuntu firewall that makes Apache server only accessible from the internal LAN? ufw status ng@ng-laptop-kv:~$ sudo ufw status Estado: activo Hasta ...
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1answer
173 views

having problem with squidGuard. Need help [duplicate]

when i write down this command on my terminal for configuring squidguard squidGuard -d this error shows up squidGuard: error while loading shared libraries: libdb-4.6.so: cannot open shared object ...
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1answer
130 views

Issues with shorewall

I'm new to using Ubuntu OS and its interface and using terminal. Recently I was trying to deploy squid, and shorewall firewall. Even though shorewall is running I can't get through one command, i.e. ...
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1answer
119 views

iptables forwarding rule

I entered the following rule into my iptables: sudo iptables -t nat -A PREROUTING -p tcp --destination-port 80 -j REDIRECT --to-ports 1337 and then when I went to remove it, I couldn't find it ...
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1answer
1k views

Connecting to NAT virtualbox guest from bridged network

I've setup a Virtualbox Ubuntu 12.04 server using Vagrant. I can ssh to it and even ping my desktop from it. What doesn't work is to ping the guest OS from my desktop. I've tried to flush the ...
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1answer
318 views

UPNP - How to configure GUFW

I have a TP-LINK TD-W8968 router with a mediaserver (UPNP/DLNA) port. The port has a USB stick with media content. I can access this content via XBMC and Totem/Movie player without any hassle. But ...
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2answers
2k views

How to block all but one or two websites without browser extensions? [duplicate]

I want to block all, but one or two websites. This question is therefore relatively close to, but different from the following Parental controls with different settings for different users ...
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1answer
123 views

UFW python documentation

I'm trying to access ufw with python, but on line 53 of backend.py, they raise a weird error that makes no sense: Traceback (most recent call last): File "mymodule.py", line 1467, in ...
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1answer
2k views

How to make ubuntu gateway?

i am new on Ubuntu. i want to make a gateway. i have some 25 systems and switch but i don't have any server. i want to setup a system as a gateway system and want to make a firewall. i want that ...
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1answer
3k views

Apache (and other services) work on localhost, but not IP address

My Apache server is working correctly on port 80. When I try to enable SSL on port 443, I can connect via localhost (telnet localhost 443) but not via IP address (telnet xxx.xxx.xxx.xxx 443). To ...
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1answer
675 views

Why ufw is blocking my outgoing traffic?

Here is my status: $ sudo ufw status verbose Status: active Logging: on (medium) Default: deny (incoming), allow (outgoing) New profiles: skip To Action From -- ...
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1answer
780 views

How to configure a firewall that only allows a few webpages and dropbox and U1 services?

Can anyone give a step-by-step how-to that explains how to block all outgoing internet traffic to all websites, but allows only a selected list (needed for working, fi. online dictionaries) allows ...
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1answer
265 views

Screen Sharing Behind Firewall

I've setup my brother's computer with Ubuntu. I would like to be able to control his screen with his permission, to configure and instruct him when needed. However, he is on a provide IP provided by ...
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1answer
104 views

How does ufw handle conflicting rules?

I recently had the following conflicting rules on ufw 445/tcp ALLOW 192.168.1.0/24 445 DENY anywhere 445 DENY anywhere IPV6 ...
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112 views

Help with ssh between machines on local network [duplicate]

I have two machines on my local network (both with Ubuntu 10.04) and I want to ssh (and rsync) between them. The two machines have fixed IPs 192.168.0.15 and ...17 Both computers frequently ssh ...
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917 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
177 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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0answers
892 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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1answer
133 views

How do you install and configure TuxGuardian in Ubuntu 12.04?

Can anyone guide me on the process to install TuxGuardian in Ubuntu 12.04? Its a freeware application available at: http://tuxguardian.sourceforge.net
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398 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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1answer
117 views

iptables help needed in 1304

I've setup my raring-ringtail machine and decided to use iptables after removing ufw to have more control over my network security. However, I'm stuck at one point. First, I've set default policy to ...
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1answer
3k views

Postfix is timed out while sending

I have just set up postfix (with tasksel install mail-server) with the default settings. Unfortunately, I can not send e-mails from by SMTP server. Here is my main.cf: # See ...
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0answers
263 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 ...
4
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1answer
420 views

Could someone tell me whether my OS is communicating with the internet?

I edited iptables so that when the VPN service is disconnected, no program will access the internet. Well, I did an experiment. I disconnected the VPN service manually and immediately did a ping by ...
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1answer
347 views

Change UDP port with iptables for VPN clients

What I want to do is say that for all UDP connections on interface ppp0 that have a destination port of 53, change that destination port to 1053. I am attempting to change the destination port of UDP ...
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2answers
1k views

Cannot open port

I've been struggling to open the port 5432 for remote PostgreSQL access. Which I installed on a Ubuntu 10.04 desktop machine. Here is the shell log: xybrek@ubuntu:~$ sudo ufw allow 5432 [sudo] ...
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72 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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2answers
2k views

Why is ufw logging 'BLOCK' messages regarding a port for which ufw is configured to 'ALLOW' connections?

Here's an example log message: May 25 10:36:07 myserver kernel: [7057243.392334] [UFW BLOCK] IN=eth0 OUT= MAC=00:02:55:67:82:eb:00:06:b1:3a:ef:62:08:00 SRC=69.197.128.26 DST=192.168.100.101 LEN=44 ...
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0answers
175 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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2answers
22k views

SSH connection refused when connecting remotly

I set up my Ubuntu server and it can connect to itself when running ssh localhost. However, when I run Putty on windows 8 I get a "connection refused" error. I have, to the best of my ability: ...
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2answers
1k views

ufw firewall operation

I have always run the program UFW as my firewall in Ubuntu, and been satisifed with its performance. When I installed Ubuntu 13.04, and enabled ufw, I was not able to access the internet, and all ...