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

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Managing parallel rules for ipv4 and ipv6 iptables?

We've recently started experimenting with IPv6, and one of the first issues we're having to contend with is dealing with a completely separate set of firewall (Linux iptables/ip6ables) rules for the ...
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2answers
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Virtualized firewall under Hyper-V?

We are currently considering installing an instance of pfSense on our Hyper-V R2 based server to act as a content filter, captive portal and general firewall. Although it is usually bad practice to ...
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3answers
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What are the named ports for iptables?

When setting up iptables you can name the port ssh which will use port 22. Is there a list of all the named ports? Specifically I need ssh, http, https and mysql.
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3answers
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What is the ip range of EC2

I'd like to setup a rule to block ssh request from EC2 since I've been seeing a large amount of ssh based attack from there and was wondering if anyone knew what their IP ranges are. EDIT: Thank you ...
7
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6answers
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Firewall anti-patterns?

What are some of the most common and wrong ways to configure a firewall? I'll start the list with the following: Blindly blocking ICMP. This was common practice in 1998 when smurf attacks were all ...
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3answers
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Running a webserver behind a firewall, is it secure?

Currently we have a Linux-based firewall which NAT-ing our public IP address to give internet access to our staff's PCs and a Windows Server 2003 for internal filesharing. I want to host Redmine/SVN ...
7
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2answers
371 views

How to configure a small network of computers within a larger university network?

I have a small computer lab (8 HP workstations, 1 HP server, 2 NAS boxes, 1 HP networked printer) where currently all the devices are connected directly to my university's network. Each device has an ...
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2answers
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tcp flags in iptables: What's the difference between RST SYN and RST and SYN RST ? When to use ALL?

I'm working on a firewall for a virtual dedicated server and one of the things I'm looking into is port scanners. TCP flags are used for protection. I have 2 questions. The rule: -p tcp ...
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7answers
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Is there a personal firewall for Linux / Ubuntu? [closed]

I am looking for some kind of personal firewall for Linux, that will monitor all outgoing connections and show me a message asking for permission to open that connection. Like the popular personal ...
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1answer
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Can I use ufw to setup a port forward?

Im currently using ufw to enforce some basic firewall rules. Is it possible to also use ufw to do port forwarding? Specifically im wanting to forward incoming traffic to my server (same machine ...
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7answers
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Linux equivalent of pfsync+carp for failover firewall/routing

I'm currently using a linux box to handle my firewall/NAT using iptables. It has two NICs, one link to a LAN switch, one to our egress Internet provider. I'm looking at upgrade this box to two boxes ...
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4answers
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What to do with an out-of-warranty Barracuda Spam/Web filter?

I'm working with an organization that would like to start using a old Barracuda Spam Filter 300 unit. I've sold and configured plenty of these, but was surprised to see that this unit's warranty ...
7
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2answers
672 views

Why are people trying to connect to my network on TCP port 445?

I was playing with my new syslog server and had my m0n0wall firewall logs forwarded as a test, I noticed a bunch of recent firewall log entries that say that it blocked other WAN IPs from my ISP (I ...
7
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2answers
162 views

Still worthwhile to firewall/filter ssh access except from specific IPs?

A number of years ago now, there were several remote exploits for OpenSSH which prompted many admins including myself to start filtering port 22 at the network perimeter, permitting only IP addresses ...
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3answers
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OpenBSD/FreeBSD Firewall w/ GUI that is compatible with Intel 82574L Gigabit LAN NICs

I recently purchased a server to run m0n0wall or pfSense but I've learned since then that both of these firewall products are based on versions of FreeBSD which weren't yet compatible with the NICs in ...
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2answers
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Block IP on EC2. Firewall or other options?

My EC2 (Fedora AMI) based service is being heavily hit by a rogue misconfigured client. What options do I have to block the IP of this rogue client?
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3answers
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What's wrong with using windows firewall?

I was developing a system which requires connection between two computers. I decided to connect the two machines together via direct ethernet cable. My boss didn't like it as there is no firewall in ...
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6answers
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Which linux-based firewall?

We are looking to replace our current aging firewall/router with a new one. We would prefer it to be free/opensource if possible. Our minimum requirements would be: 1) Site-to-site VPN 2) Web ...
6
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2answers
347 views

When an IP or a block of IPs are assigned to you, do the network admins just add them to a router?

Let's say there is a router to the internet and a router separates your network from others within a data center. When the data center provided gives you IP addresses, do they just take a [set] of ...
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2answers
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pfSense Firewall or Linksys/Cisco router for small offices

I'm about to start switching some networks around for multiple small offices. Each office has about 10 to 15 users and 10 to 15 computers. Each office has a spread of generic routers and access ...
6
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3answers
292 views

Is there already a recommended IPv6 Firewall setup?

I'd like to switch from private-IPv4-subnet-behind-NAT to IPv6, but of course I have no intention of exposing my users' workstations "unprotected" to the net. Some obvious points up-front: Allow ...
6
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5answers
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Disable Windows Server Network Locations

I'm not sure what exactly this feature is called. But in Windows Server 2008, it has the Vista Public/Private/Domain locations. This makes sense for laptops, and none at all for servers. My problem ...
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2answers
531 views

Gigabit network with a 100 megabit firewall

We have set up all the equipment necessary to have a gigabit network. All servers + workstations are running gigabit cards, just bought a 16 port switch that can handle gigabit as well. My concern is ...
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9answers
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Need prosumer router/firewall/vpn/vlan/nat advice [closed]

Looking for a recommendation on a device (or devices I guess) to do router/firewall/vpn/vlan/nat functons for my home network. Right now, I'm doing this with an IPCop box, but I'd prefer a little ...
6
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1answer
133 views

Techniques to implement iptables rules

Usually a limited amount of services are configured on a server and most of the not needed ones are shut down, I was wondering what would be the best approach to firewalling with iptables. Is it ...
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3answers
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Disabling Windows Server 2008 firewall

I applied a Windows firewall rule that blocks all tcp connection and thus kicked myself out of remote desktop on a dedicated server. I managed to get into recovery via VNC, which is basically a ...
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3answers
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Firewall blocking FTP server on Windows 2008 R2

I can access the FTP site without problems from the local machine, but it times out from the remote machine. If I turn the firewall off COMPLETELY, it works. Obviously, this isn't really a ...
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3answers
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Rate limiting with UFW: setting limits

UFW's man page mentions that it can setup iptables rate limiting for me: ufw supports connection rate limiting, which is useful for protecting against brute-force login attacks. ufw ...
6
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3answers
5k views

IPTables: allow SSH access only, nothing else in or out

How do you configure IPTables so that it will only allow SSH in, and allow no other traffic in or out? Any safety precautions anyone can recommend? I have a server that I believe has been migrated ...
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5answers
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How do I scan a firewall to find open outgoing ports?

I'm looking for a tool that I can use within a firewalled network to scan the firewall to find open outgoing ports. I've done some research and found Firewalk but it hasn't been maintained in 10 ...
6
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1answer
112 views

Tools for detecting network traffic filtering [closed]

In Iran we have an ongoing problem with the govt. blocking and manipulating various network protocols. I'm looking for a tool, framework or platform to help us analyze and report on any of these ...
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5answers
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“No route to host” with ssl but not with telnet

I have a strange problem with connecting to a https site from one of my servers. When I type: telnet puppet 8140 I am presented with a standard telnet console and can talk to the Server as ...
6
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1answer
372 views

Cisco FWSM -> ASA upgrade broke our mail server

We send mail with unicode asian characters to our mail server on the other side of our WAN... immediately after upgrading from a FWSM running 2.3(2) to an ASA5550 running 8.2(5), we saw failures on ...
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2answers
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Is there a secure way to allow IIS 7 in a DMZ to access a DB server behind the firewall?

Our network admins are adamant that it is insecure for our web servers, which are hosted in the DMZ, to access the DB server behind our firewall. To get round the problem, we access the data via web ...
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5answers
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DDoS Protection Services - are they good enough? [duplicate]

first of all, I understand that it's better to have DDoS protections on data center level. But our DC is not ready to provide good quality of protection. So we thinking about using some external DDoS ...
6
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3answers
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Border firewalls and routing — static vs dynamic routing

Let's say you've got an enterprise with a small internet presence in the form of a DNS server, a web server, and a VPN server, all on the DMZ (in this case, an invisible pair of switches connected ...
6
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2answers
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Linux iptables / conntrack performance issue

I have a test-setup in the lab with 4 machines: 2 old P4 machines (t1, t2) 1 Xeon 5420 DP 2.5 GHz 8 GB RAM (t3) Intel e1000 1 Xeon 5420 DP 2.5 GHz 8 GB RAM (t4) Intel e1000 to test linux firewall ...
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9answers
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Block users from Social networking websites while firewall is down

We currently have a SonicWall firewall, which does a pretty good job a blocking Social networking websites like Facebook and Bebo. The problem we are having is that sometimes we need to temporarily ...
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3answers
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Hardware alternative to PfSense software Firewall/Router

I have been using PFSense on a PC for about 4 years now for my home network, and it works perfect. I love all of its features and I really cannot complain. Recently though I have been getting tired ...
5
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9answers
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block Torrent through firewall

is there a way to block users on firewall level from using torrents?
5
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3answers
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Where does UFW (uncomplicated firewall) save command-line rules to?

You add a rule like this: ufw allow 22/tcp The rule is saved, and is applied even after reboot. But it's not written anywhere in /etc/ufw. Where is it saved to? (Ubuntu, using ufw as ...
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6answers
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Why block outbound ICMP?

This question is slightly related to "Why Block Port 22 Outbound?". I don't see how this can be a notable security risk.
5
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2answers
404 views

Where does a firewall application fit into the software stack?

I'm trying to figure out where a firewall application on a server fits into the software stack, and at what point in the networking process the firewall "kicks in," from the perspective of an ...
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8answers
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Why Place Load-Balancer Behind Firewall?

I'm considering purchasing an F5 load balancing device which will proxy inbound HTTP connections to one of five web servers on my internal network. My assumption was that the F5's external interface ...
5
votes
2answers
175 views

What is an “application firewall”?

Trying to find out more about apple's "Firewall". What exactly is it? In /usr/libexec/ApplicationFirewall there are a bunch of undocumented programs, I've wandered through the mystery maze of ...
5
votes
1answer
732 views

Cannot modify iptables on CentOS

My question: How to add a custom iptables rule to accept connection on a certain port? I'm trying to open port 3500 on my server but failed. I started by using this command: (From ...
5
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5answers
767 views

NAT as a firewall

Network Address Translation ( NAT ), seems to sort of act as a firewall for the hosts behind it because they are not available. Although I would never rely on this as my firewall, what are its ...
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4answers
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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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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 ...
5
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1answer
134 views

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 ...