A Firewall is an application or hardware device used to inspect and filter network traffic.

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Home Network, router firewall vs Windows firewall [closed]

Similar to these questions: What Firewall Rules Should Be Used For A Home-Based System and Firewall on VPS Use Windows Built In But more specifically I'm guessing that using both the Windows Firewall ...
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2answers
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Symmetric NAT and UDP Hole Punching

I've read this question, but the explanation of Symmetric NAT wasn't detailed enough. Please could someone help me to understand the following paragraphs? I read this about Symmetric NAT: Each ...
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3answers
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How can I block a specific type of DDoS attack?

My site is being attacked and is using up all the RAM. I looked at the Apache logs and every malicious hit seems to simply be a POST request on /, which is never required by a normal user. So I ...
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1answer
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Do you have to have two servers to put Exchange 2010 on the Internet?

I was reading about the Edge Transport Role on Exchange 2010. It looks like this is the only way to put Exchange the Internet. Is this true? Also, doesn't this require a second hub transport server?...
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5answers
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Blocking a country (mass iP Ranges), best practice for the actual block

This question has obviously been asked many times in many different forms, but I can't find an actual answer to the specific plan I've got. We run a popular European Commercial deals site, and are ...
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3answers
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Placing a server in the DMZ vs opening firewall ports

When should you place a server in a DMZ vs opening ports on the firewall and keeping it within the network? I'm referring to active directory servers, IIS servers, and mostly things on a windows based ...
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6answers
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Advice a good hardware firewall [closed]

Which firewall would you advice to use to meet following 1Gb line and most anti hacking modules. Price range 10k-15k$. 3 years warranty on site, full support online. About modules, i don't know what ...
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700 views

iptables: change policy or use catch-all rule?

What do you do when setting up iptables: change the default policy (iptables -P INPUT DROP, for example) or add a catch-all rule at the end of the ruleset (iptables -A INPUT DROP)? If you do prefer ...
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4answers
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iptables, blocking large numbers of IP Addresses

I'm looking to block IP addresses in a relatively automated fashion if they look to be 'screen scraping' content from websites that we host. In the past this was achieved by some ingenious perl ...
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1answer
104 views

Do I need to open any port for NTP synchronization to work if both outgoing and incoming are blocked on ufw?

One of my production servers, UFW configuration is as follows: Status: active Logging: on (low) Default: deny (incoming), **deny (outgoing)**, disabled (routed) New profiles: skip To ...
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3answers
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How to create a Windows 2008 Advanced Firewall rules group definition through the command prompt

Is there a way to create a group, or add to an existing group, to a rule in Windows Advanced Firewall (preferable through a command prompt or WSH script). Edit:
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1answer
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Windows Firewall IP ban?

OK, question: I have a IIS webserver and Windows firewall. To allow incoming connections to IIS, I enabled port 80 and 8080. But now, how can I block a specific IP address/range on port 80 (=ban) ...
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2answers
491 views

How to allow UDP broadcast between interfaces on a Cisco ASA 5506-X

I have a CISCO ASA 5506-X with 4 configured interfaces and a set of access-lists etc. It is configured via CLI and is running in routed mode, not transparent. Everything is running well, but now I ...
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1answer
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Why is pfSense blocking multicast traffic when it is explicitly enabled?

I have a pair of pfSense firewall/routers set up in CARP/XML Config cluster. On the LAN side, the switch also has a pair of servers running corosync/pacemaker/drbd. These are on a different ip network,...
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4answers
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ufw blocking apt and dns

I installed ufw on my Debian system like the following: # aptitude install ufw # ufw limit 22 # ufw allow 80 # ufw allow 443 # ufw enable # ufw status verbose Status: active Logging: on (low) Default:...
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2answers
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Secure NAT setup with iptables

I have a Debian running device that needs to act as an internet-gateway. On top of that I want to provide a firewall that not only blocks inbound traffic, but also outbound traffic. And I figured ...
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2answers
316 views

Portable firewall rules for Linux and Free/Net/Open/DragonFlyBSD

I need apply the same rules (lists of IPs with allow and drop rules) in firewalls of Linux and *BSD. Do you know some application (CLI) for to convert a list of rules in the specific format of each ...
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2answers
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Firewall still blocking port 53 despite listing otherwise?

I have 3 nodes with virtually the same iptables rules loaded from a bash script, but one particular node is blocking traffic on port 53 despite listing it's accepting it: $ iptables --list -v Chain ...
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2answers
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What ports should be left open on a web server?

I'm going to try deploying my first web app soon, so my experience is lacking. I remember reading somewhere that port scans by bots happen within minutes of being exposed to the internet (maybe that'...
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1answer
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Linux NFLOG - documentation, configuration from C

Several different places (e.g. http://wiki.wireshark.org/CaptureSetup/NFLOG) recommend using Linux's "NFLOG" firewall module to capture packets generated by a particular UID, like this: # iptables -A ...
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1answer
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pf slows traffic extremely down

I am running a web and mail server on FreeBSD 9.1. The system is installed on a KVM vServer. Everything works fine - until I enable pf(4). My weblog becomes unconscionably slow. So does all the other ...
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1answer
592 views

Block Google requests to 16k using pf firewall

I'd like to block access to Google search using PF after the threshold of 17500 requests (connection established) in 24h, from a host running FreeBSD 9. What I came up with, after reading pf-faq is ...
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1answer
451 views

Configuring firewallD in Fedora 18/19

I am new to firewallD and have been going through the documentation but I thought maybe I can discuss some things here with everyone. So I see that firewalld has now replaced the iptables service as ...
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3answers
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psexec Couldn't access \\IP/computername The system cannot find the path specified

Tried psexec \\ip.add.re.ss -accepteula -u local_admin -p cmd.exe psexec \\computername -accepteula -u local_admin -p cmd.exe psexec \\computername.fdqn -accepteula -u local_admin -p cmd.exe where ...
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Restrict Computer or Users from Internet but allow access to intranet and Windows Update / ePO?

So this may be impossible but I've been asked to try and find something about it. So far nothing I have found is possible. I need to restrict specific machines or user accounts from regular Internet ...
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iptables — OK, **now** am I doing it right?

This is a follow up to a previous question where I asked whether my iptables config is correct. CentOS 5.3 system. Intended result: block everything except ping, ssh, Apache, and SSL. Based on ...
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2answers
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Storm Botnet on Linux?

We have a customer who is running an office CCTV system which he accesses from home. The system runs on an embedded Linux box behind a NAT firewall forwarding to ports 8080 for web browser access and ...
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1answer
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Cisco ASA Config for PCI Compliant Office

We have a small business office, but due to PCI compliance we need to segment this into two internet networks (one 'compliant' and one for any other devices to use). We currently have a Draytek modem/...
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2answers
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Is there a way to run FTPS on Windows Server 2008 / FTP 7.5 through a Firewall?

I'm attempting to setup a FTPS server on Windows Server 2008. The inner workings have been successful -- I can connect locally or on the VPN. But I can't seem to craft the firewall rules to make it ...
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2answers
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Linux fails to interpret ACK, keeps resending SYN+ACK

The following is a wireshark dump of the problem occurring, IP-adresses replaced with 'client' and 'server': 4414.229553 client -> server TCP 62464 > http [SYN] Seq=0 Win=65535 Len=0 MSS=1452 ...
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5answers
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iptables vs. hardware firewall

I was wondering if anyone could speak to the advantages of a hardware-based firewall vs using iptables directly on a web server. I'm evaluating the cost effectiveness of having a dedicated firewall ...
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1answer
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Can't connect to MySql server on remote server

Connecting to: CentOS v?? with MySql 4.?? in Nashville (example public ip=11.11.11.11) Stack: Cable modem as gateway > router with forwarding > CentOs Box Connecting from: Windows 2003 R2 in ...
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iptables port forwarding on debian

I'm trying to setup a simple port forwarding firewall and I can't make the basic non-firewall configuration to work. I have setup the iptables script as follows #!/bin/sh # interfaces LAN="eth1" ...
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2answers
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How should I set up my Hyper-V server and network topology?

This is my first time setting up either Hyper-V or Windows 2008, so please bear with me. I am setting up a pretty decent server running Windows Server 2008 R2 to be a remote (colocated) Hyper-V host. ...
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IPset Alternatives and Firewall Management

I have CentOS 7, Plesk 12, 8GB RAM VPS. I have around 1000 rules in my IPtables to block abusive users. But when reloading IPtables it takes 15 seconds to reload all 1000 rules. First of all, is it ...
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Small business firewall/VPN device [closed]

What's a good small business (<50 users at a location) firewall and VPN device? Wireless would be a nice addition, and I'm thinking of something in the $1,000 range. This would be for businesses ...
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12answers
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Should you run firewalls inside your network perimeter?

The age-old question. I've seen responses go both ways on this, but never a comprehensive answer as to why you want firewalls active within your trusted network. When I say "trusted", I (typically) ...
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7answers
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Dedicated firewall vs. on-machine

I'm setting up a bunch of Ubuntu servers in a colocation center. They offer a shared firewall service, but suggested I install a firewall on the servers myself, i.e. configure iptables on each machine ...
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2answers
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Should I use TCP or UDP to run a web server

I have just installed Apache web server on my computer. I have managed to use it locally (I can open index.php from my computer using my web browser). But I would like to make my web site available ...
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6answers
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Are there any security benefits to having a dedicated firewall?

Are there any security benefits to having a dedicated firewall rather than having a firewall established on a router? Thanks.
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“account currently disabled” when accessing share, even before logging in

When I try to access a share folder, say \\share-folder, I get the following error message: logon failure: account currently disabled This seems strange to me, since there is no 'account' to be ...
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2answers
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Content Aware Firewall and Encrypted Content

There are firewalls out there that analyze the traffic that goes through and block it if it is not wanted. How good do these firewalls work with encrypted traffic, e.g. HTTPS or IMAP over SSL? An ...
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3answers
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How long does it take for an iptables rule to apply?

How long does it take for an iptables rule to apply? I use a script with the code below in an attempt to block hosts, but they don't appear to take immediately. Is there some delay, is iptables not ...
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4answers
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What are the risk if all Outgoing connection/ports are open?

To solve facebook authorization connection on our server, we've decided to open all outgoing connection/ports in firewall to see if it's really security issue. after allowing, the facebook connection ...
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3answers
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Comparison of Firewall, Intrusion Prevention, Detection and Antivirus Technologies in Organizational Network Architecture

in these days i'm reading about intrusion prevention/detection systems.When reading i really confused in some points. First, the firewall and antivirus technologies are known terms for years, however ...
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Why is my port 25 so active?

Using netstat -na I notice that I have a lot of connections like tcp 0 0 XXX.XXX.XXX.XXX:25 YYY.YYY.YYY.YYY:13933 ESTABLISHED tcp 0 0 XXX.XXX.XXX.XXX:25 ZZZ....
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When would I open Port 53 for DNS?

Locking down an application server. The server hosts a web app that is served via http. There are a few other ports open as well. Port 53 is open for DNS. Why would I need this? Extra: (Do not ...
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1answer
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Iptables - allow traffic from entire 10.x.x.x

Is there any way to configure iptables to ACCEPT the traffic from 10.anything? currently I have the rule to the single address, but I want the entire range: sudo iptables -I INPUT --src 10.240.74....
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4answers
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What host names and ports would need to be opened in a firewall to allow Windows Updates to work?

We have a set of public web servers behind a firewall we would like to be able to perform Windows Updates on, without giving them more access than they need. Besides www.update.microsoft.com:443, ...
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2answers
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Standard Firewall and Network Change Testing Procedure

I am looking for a standard that advises on the best practice for testing of the following situations: Network Changes Firewall Changes Does any standard exist? If so, please note where I can find ...