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

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How to relax firewall for UDP connections/ports for a specific IP address?

My server is Red Hat Enterprise Linux Server release 5. iptables version is v1.3.5. I want to allow all UDP connections / port for the IP address 192.168.0.200. This IP address is configured in my ...
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1answer
2k views

Multiple interface NAT routing

I have multiple internet connections from different ISPs and I need to route certain traffic over a particular ISP link. I am using Debian for this. The setup is as follows; eth0 (IP address is ...
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3answers
287 views

iptables — am I doing this right?

UPDATE Boy am I glad I asked. OK, I'll try again and post another question. I'd like to set up a CentOS 5.3 host to allow only ping, ssh, httpd, and SSL connections. After reading a tutorial and ...
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2answers
257 views

Debugging iptables and common firewall pitfalls?

This is a proposed Canonical Question about understanding and debugging the software firewall on Linux systems. In response to EEAA's answer and @Shog's comment that we need a suitable canonical ...
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3answers
319 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 ...
5
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1answer
378 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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9answers
3k views

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
2k views

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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2answers
9k views

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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1answer
648 views

Need help understanding capturing from Wireshark?

I am having issues with my FTP servers. Connecting, sending and receiving fail sometimes, and it is not consistent. I manage to capture and filter by IP the packets, I just need pointers on what can ...
3
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1answer
1k views

Rotating outgoing IPs using iptables

I am trying to rotate outgoing IPs using iptables. I want to rotate outgoing connections between three IPs, one by one. Here is what I'm doing with iptables: root@server:~# iptables -t nat -I ...
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3answers
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Enabling http access on port 80 for centos 6.3 from console

Have a centos 6.3 box running on Parallels and I'm trying to open port 80 to be accesible from outside tried the gui solution from this post and it works, but I need to get it done from a script. ...
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3answers
18k views

What does “incoming” and “outgoing” traffic mean?

I've seen many resources explaining how to set up a server's firewall to allow incoming and outgoing traffic on HTTP standard ports (80 and 443), but I can't figure out why I would need either of ...
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4answers
1k views

Is it alright to turn off firewall in a LAN using Group Policy?

Is it a good idea or common practice to completely turn off windows firewall in an AD domain using Group Policy? At this time, even the servers' firewall are turned off. The only device not affected ...
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2answers
429 views

Is my linux firewall secure?

I am newbie to linux firewalls and trying to setup my systems firewall for a public facing computer. Here are my requirements: Ports 80 and 22 should be open for HTTP requests and SSH logins Since ...
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5answers
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Apache DDoS Protection in router (pFsense) [duplicate]

I'm soon going to change my infrastructure when I buy a new server. I'm going to replace my D-Link DIR-655 router with an pFsense router (and probably use the 655 as an AP) using my old server ...
3
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2answers
7k views

Why can't I ssh or ping my brand new Amazon EC2 instance?

I just created a free EC2 instance with all the defaults. It says it's running in the AWS Management Console. On the "Instance Actions" menu, I click "Connect". I copy the DNS name provided (looks ...
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7answers
4k views

4 NICs or 4-port NIC?

I want to setup a firewall handling two ISP connections and two routers. For that I am planning to use an old Pentium 3 machine. Now, should I use four network interface cards or a 4-port NIC? Do ...
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7answers
867 views

Is Windows 2003 Firewall appropriate for a web server?

I currently have a colocated server being protected by a hardware firewall, however this firewall is old and I want to replace it. I was wondering if the built-in Firewall software for Windows 2003 ...
3
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1answer
801 views

Will you allow NetBIOS into your DMZ?

Is it secure for a firewall to allow NetBIOS connections from the internal network to the DMZ? If not secure, what are the risks? If secure, what is the FUD about and what are the counterarguments? ...
2
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2answers
337 views

How to have ntpd serve only my local subnet

I have a few servers with public Internet IP addresses like A.B.C.x. One of my hosts (A.B.C.10) runs ntpd and I have it syncing it's time from europe.pool.ntp.org. Now I only want to allow hosts ...
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2answers
3k views

How to log the ip addresses trying to connect to a port?

Is it possible to log all ip addresses that trying to connect or connected to port "5901" in linux debian? how can i do that? Regards
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2answers
824 views

Virtualizing Firewalls/UTM

So Sophos UTM (Astaro Gateway UTM) can be virtualized in Hyper-V, VMWare, vSphere etc. Now I'm new to virtualization, so am wondering how the networking would be configured in this situation. ...
2
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1answer
277 views

Examples where an AWS Security Group is not sufficient as a firewall?

Currently I am using only an AWS security group for one of my EC2 instances but have given some thought to adding a firewall to that stack as well. I'd be looking at using either iptables, or ...
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2answers
4k views

Ports used for Lync Edge server

I have Lync 2010 Standard deployed in my environment, along with an edge server. On my firewall I have NAT'd the public address(s) to the server. Right now I have all the ports opened for these ...
2
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1answer
731 views

iptables: block traffic by IP range for specific website

there is a web-hosting server with several sites on it. I need to block some subnets (IP ranges) for some website(s). Is it possible at all? I've tried something like this: iptables -A OUTPUT -m ...
2
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1answer
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User Friendly port knocker (port knocking client) for Windows?

It seems "It's me" is the most popular port knocking client for windows… Except… it sucks. It works for console-savvy users such as me, but, unsurprisingly, all my users (3 people) hate console ...
2
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1answer
3k views

HOw to check firewall rules in Centos

I have centos 5. I tried iptables -L and it gives the following output Chain INPUT (policy ACCEPT) target prot opt source destination RH-Firewall-1-INPUT all -- anywhere ...
2
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2answers
460 views

How long does a blocked connection from Iptables last? Is there a way to set the timeout?

iptables -A INPUT -m state --state NEW -m recent --set # If we receive more than 10 connections in 10 seconds block our friend. iptables -A INPUT -m state --state NEW -m recent ...
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2answers
199 views

Just LB or also Web Servers in Demilitarized Zone?

In a load balanced environment, is it necessary to have all of the web servers in the DMZ? Or will just having the Load Balancer in the DMZ achieve the desired security? If it matters, the web ...
2
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2answers
4k views

Disable firewall, ubuntu 9.04

How can I disable firewall on ubuntu, or how can I check which ports are listening, and how can I add some new ports to be listened to? Thank you
2
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2answers
1k views

Smoothwall NOT giving out DHCP

I have a Smoothwall machine with 'green + red' setup. The Smoothwall machine can see the outside world and I can connect to it from inside my network with its local address (I can also connect from ...
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2answers
9k views

Windows Firewall 2008 Server - Allow only given IP in, block all others

I've got a Windows 2008 Server. It has the built-in windows firewall on it. I've played around with the Advanced settings where I can setup inbound/outbound rules, but it doesn't appear that I can ...
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3answers
628 views

Mac OS X Firewall Configuration: what's the easiest way to do it?

On occasion I need to configure the firewall on OS X machines (10.5), and I've been trying to figure out the best (read: easy without sacrificing too much control) way to do it. So far it seems like ...
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1answer
41 views

TLS Error: Handshake failed. Openvpn Server is behind NAT on dynamic ip

this is a common problem that appears easily in searches and seems to be related to the firewall , yet I can't seem to figure out how to fix it. I have actually asked before, but this time I come back ...
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1answer
642 views

Limit Connections Per IP Windows 2008 R2 x64

Hello I have been searching for a solution to this, what I want to accomplish is the ability for me to define firewall rules that will limit the amount of connections to certain ports from the same ...
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0answers
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Mikrotik router RDP brute force blocking with whitelist

Masters, We have a miktorik router, and we would like to block RDP brute force, but we need whitelist also to allow our collegaues to connect without blocking them. (they sometimes hitting wrong ...
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0answers
119 views

Wireless Bridging two Sonicwall Firewalls

We have two sites (essentially two small buildings side by side but we are unable to run CAT5 cable between them) which are currently linked via a wireless bridge. We will be splitting the sites so ...
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3answers
424 views

Netflow/IPfix Analyzer for network threats and anomalies

I'm evaluating various options for Netflow/IPfix based analyzers which focus on identifying security threats and anomalies. It would be highly appreciated if someone can provide a list of tools with ...
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1answer
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iptables rule order

I have noticed the following iptables rule order executed by a program: iptables -A INPUT -p all -j ACCEPT iptables -A INPUT -p all -s ip_address -j REJECT I thought that based on the ordering ...
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4answers
4k views

How to route external TCP port 80 into loopback (127.0.0.1) port 8080?

I have a test VDS box with real IP. If i start web server on physical interface port 80, it can be opened from another computer via it's ip address (and default port 80): python -m SimpleHTTPServer ...
1
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1answer
187 views

Directory Listing (ls) error ONLY in port 22 (SFTP)

Using SFTP I suddenly get this result: Status: Connecting to 64.207.146.82... Response: fzSftp started Command: open "root@64.207.146.82" 22 Command: Pass: ********* Status: Connected to ...
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1answer
1k views

Firewall predefined rule property cannot be modified

Using a stand alone Windows Server 2012 Standard edition (no Active Directory), I Tried to establish a simple remote desktop with a custom port number, but could not modify the port number in the ...
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1answer
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Config Server Firewall: Spamming my email | lfd on localhost: Suspicious process running under user www-data

I have just installed and configured CSF and I am getting 100s of spam emails containing this message. lfd on localhost: Suspicious process running under user www-data Time: Wed May 23 01:05:52 ...
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3answers
6k views

FTP Transfer Very Slow When Windows Firewall Enabled

We have a scheduled task that transfers a large file (~130 MB) between two Windows servers using the Windows command-line FTP program. It's painfully slow (taking about 30 minutes) and occasionally ...
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3answers
823 views

Linux : restricting outgoing on an application basis

I typed : netstat -atlpvn and noticed that applications like gedit and python had foreign addresses outside the network (the network being a single computer connected to the internet). Is there ...
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1answer
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Recovering a server from being an open relay

One of our Mac Pro machines running Apache was inadvertently acting as a forward proxy with a public IP, after some organisation proxy rules changed. Consequently it was discovered by spammers and ...
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3answers
2k views

Unable to access internal network through PfSense WAN port

Our branch office is unable to connect to our internal network for some reason. However we can connect to the branch office domain controller from behind PfSense. The following is our setup: ...
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4answers
143 views

Do I need a hardware firewall for Win 2003?

We have had a Win 2003 server at a co-lo for a while. It is used as a web server and has a very cheap hardware firewall between it and the internet. Ports 3389 and 80 are the only ones forwarded to ...
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3answers
570 views

Windows Server 2008 firewall: do I need to set outbound rules?

In Windows 2008 I see inbound and outbound rules, I can open TCP and UDP in both directions. So if I open some port in TCP and some in UDP inbound and the connection works, why do I need outbound ...