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

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4answers
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Linux router and firewall with IP accounting

I'm working on a project to replace my organisation's aging Slackware gateway/router/firewall machine, which will have several hundred users behind it. Previously we used rc.firewall but we are now ...
2
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4answers
740 views

How to browse to a webserver which is reachable through the SSH port only

I have a server at work which is behind a firewall (the company's firewall) so it is reachable only thrugh port 22 (SSH). I'm able to connect to the server with putty without problems. Also, that ...
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4answers
2k views

Securing a guest VM to give it internet access, but block access to host LAN

I have a Linux guest VM running under a Windows host. If I set the networking mode to NAT, the guest can get internet access (which I want), but can also access the hosts LAN (which I dont). For ...
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3answers
2k views

iptables rule to block incoming/outgoing traffic to a Xen container

I'm trying to setup IPTABLES on my xen host server that will block incoming and/or outgoing access to a xen client on the same machine. Specifically, I need to block outgoing port 25 traffic and ...
1
vote
2answers
5k views

pfsense setting up as transparent firewall - dhcp issue

I followed the directions to set up pfsense in bridged / transparent mode per the instructions at http://doc.pfsense.org/index.php/Configuring_pfSense However I can not get a dhcp address from my ...
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3answers
311 views

Network Question

I have a question about whether something is 'possible' by default or requires additional setup. Lets say I have two systems behind a firewall and they are in the same domain and subnet. System 1 has ...
1
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1answer
2k views

CSF firewal - how does csf.allow work?

In my csf.allow file I have (something like): 98.765.43.21 tcp:in:d=20:s=12.345.67.89 tcp:in:d=21:s=12.345.67.89 Am I right in thinking that this will 1) always allow any service for 98.765.43.21 ...
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1answer
1k views

How to stop OpenEsb Glassfish Admin console from opening connection to glassfishesb.org

I have a Glassfish v2.1 app server (OpenEsb distribution) running behind a very restrictive firewall. Some times a bottom frame will appear, trying to connect to this address: ...
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5answers
9k views

Best way to block Windows Workstations from receiving Microsoft updates

I have a network with 10,000 workstations that are all currently trying to download SP3 and are flooding the network (this was do to an errant AD policy change). What is the best way to block this ...
0
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1answer
431 views

Can these IPv4 and IPv6 firewall rules be hardened any further? [closed]

I am running Ubuntu 10.04. Here are the IPv4 firewall rules that I've been using now for a few months: *filter #Allow all loopback (lo0) traffic and drop all traffic to 127/8 #that doesn't use lo0 ...
0
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2answers
693 views

ConfigServer Security and Firewall — after setup, how much daily management required?

I'm looking at using ConfigServer Security and Firewall (CSF; iptables-based). After I configure it properly, how much daily ongoing management is required of me to keep my server secure? Am I going ...
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2answers
451 views

Web server hardware firewall recommendations [closed]

I'm looking for a specific hardware firewall model solutions that best accommodate the following concerns [Cisco models are best, because our colo can get good deals on them reconditioned]: There ...
0
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1answer
1k views

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 ...
0
votes
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
289 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
2k views

iptables: open port 25 CentOS 7 [closed]

I have problems opening port 25 for sendmail on my CentOS 7 machine. Here's my iptables configuration: *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] -A INPUT -m state ...
7
votes
3answers
9k 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 ...
6
votes
3answers
330 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
votes
1answer
436 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 ...
5
votes
9answers
4k 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 ...
4
votes
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 ...
4
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2answers
12k 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 ...
4
votes
2answers
10k 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 ...
4
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3answers
2k views

Disable connection tracking with UFW for port 80

During load testing my server is dropping packets due to "connection tracking" way before it's running out of resources. I'm using Ubuntu Jaunty with ufw. In my syslog I get: ip_conntrack: table ...
3
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1answer
541 views

With SonicWall, cannot access URL inside network

We have a website running on port 80 on our network. Port 80 is forwarded outside of the network, and it is accessible through a URL that points to the IP or the IP itself. However, inside the ...
3
votes
2answers
966 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 ...
3
votes
1answer
1k 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
votes
1answer
2k 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 ...
3
votes
3answers
13k views

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. ...
3
votes
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 ...
3
votes
4answers
15k views

Windows Firewall has port 80 open but prevents Apache from making connections

I have a Windows 7 machine serving a very few (but important!) pages. I have an exception that allows any traffic to port 80*, but Apache 2.2 still can't serve pages (though I can see them from the ...
3
votes
2answers
443 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 ...
3
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5answers
3k views

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
votes
2answers
6k views

User Friendly port knocker (port knocking client) for Windows? [closed]

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 ...
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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 ...
3
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7answers
891 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
votes
1answer
877 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
74 views

How to require all network activity to pass a KVM guest firewall before reaching the host?

Most of the information I've come across tends to set up a KVM firewall using a bridge connection. From my understanding it is a security risk if network traffic can reach the host without having to ...
2
votes
2answers
5k views

Forwarding Ports on Centos 7

I'm working on a CentOS 7 server and I'm trying to get JBoss to work the way I want it too. I'm running Java 8 and JBoss(wildly) 8. I have gotten those installed and working on the default ports, ...
2
votes
0answers
2k views

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 ...
2
votes
2answers
976 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
votes
1answer
344 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 ...
2
votes
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
votes
1answer
2k views

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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1answer
2k views

Can't ping from my Amazon EC2 instance running Windows Server 2008 R2

I have been searching for a while, but it seems like most people have same issue but in the other direction. Meaning that the can't seem to ping their Server. I am trying to use putty to access my ...
2
votes
1answer
880 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
votes
1answer
4k 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
votes
2answers
511 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 ...
2
votes
2answers
206 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
votes
1answer
228 views

Is there a robust, low-hassle solution for “port-knocking” based protection of SSH ports?

By robust and low-hassle I mean NOT involving complex iptables setups, NOT involving apache, NOT requiring an additional client program, NOT requiring fragile shell scripts running from cron, etc. ...