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

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469 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, ...
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1answer
6k 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 ...
1
vote
2answers
921 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 ...
0
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1answer
88 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
321 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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0answers
59 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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votes
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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0answers
884 views

squid with ubuntu server, iptables explanation

To begin with, I'm a linux newb. I have setup a squid proxy on my home network and it is working fine. I went through couple of tutorials to get this working. My setup is: Internet->Modem->Router-My ...
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1answer
526 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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vote
1answer
168 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 ...
0
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1answer
107 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
115 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
861 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 ...
1
vote
1answer
278 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 ...
2
votes
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 ...
3
votes
1answer
109 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 ...
0
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1answer
1k 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 ...
2
votes
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 ...
4
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1answer
637 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 -- ...
1
vote
1answer
723 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 ...
0
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1answer
242 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 ...
1
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1answer
85 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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0answers
111 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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0answers
825 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
151 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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0answers
853 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 ...
1
vote
1answer
128 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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0answers
370 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 ...
1
vote
1answer
112 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 ...
0
votes
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 ...
1
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0answers
241 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
votes
1answer
398 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 ...
0
votes
1answer
335 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 ...
2
votes
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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0answers
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 ...
3
votes
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 ...
2
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0answers
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 ...
0
votes
2answers
19k 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: ...
1
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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 ...
2
votes
1answer
236 views

Open ports for development purposes

I'm doing some Java ME Development in my brand-new Ubuntu laptop, coming from a now replaced Windows Vista one. What I'm trying to do is run a Mobile Simulator that acts as an HTTP Server -receives ...
0
votes
2answers
135 views

If I have Ubuntu installed along side Windows, does the firewall on Windows work along with the antivirus system?

I have Ubuntu installed on my Windows 7 computer. I was curious to know if the firewall on that one is activated (I have to turn it on each time I'm on the computer) along with the antivirus system, ...
2
votes
1answer
4k views

How do I allow local subnets in ufw?

I recently got IPv6 connectivity at home and now I would like to allow connections to my home server via IPv6 from the LAN only. The trick is that the IPv6 address/prefix assigned to the server is ...
1
vote
1answer
239 views

Unable to connect through Java programs in Ubuntu

I am unable to connect to any host through Java programs, getting java.net.ConnectException: Connection refused. Does it have anything to do with Ubuntu firewall configurations or any other ...
0
votes
1answer
3k views

UFW 'default deny incoming' doesn't work

I have UFW enabled, 'default deny incoming' set and no any additional rules, but I still can access all ports from other PCs. I have to manually block each port. What can be wrong?
20
votes
3answers
992 views

What automated intrusion notification/detection setup is good for home desktop use?

I've been using Linux for quite a while now and I always feel the need to have a passive software / script setup which can alert me of any suspicious network activities like scans, failed login ...
3
votes
2answers
4k views

What could be the cause for these strange UFW block entries in my syslog?

I've recently noticed a large number of recurring UFW blocks in my syslog. This surprised me as I have no UFW rules set: $ sudo ufw status verbose Status: active Logging: on (low) Default: deny ...
0
votes
1answer
792 views

How do I configure ufw to only allow outgoing/established connections for a IPv6 network?

How do I configure ufw to only allow outgoing/established connections for a IPv6 network? I am using an old computer with 12.04 installed to create an IPv6 router for my local network. I would like ...
1
vote
1answer
442 views

Setup firewall: ask user to allow new incoming/outgoing traffic?

I'm using Ubuntu 12.10 and as I know there is already a firewall on any ubuntu system. It's ufw and because I like fancy gui stuff I can use gufw, that's very nice. Now I would like to configure this ...
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votes
4answers
1k views

Reverse Firewall or Application Firewalls?

Firewalls are typically employed to prevent bad "packets" coming in from the outside world. But these days we are mostly behind routers and a lot of that danger is mitigated by the router. The danger ...
0
votes
1answer
302 views

Forward [open] Ports 7777; 2106

Hi i am new to Ubuntu (12.10) x64 Trying to forward ports for gameserver on my pc (Lineage II) Ports are opened in UFW Ports are opened in my Router Even if i disable UFW others still cant login to ...