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

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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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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 ...
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1answer
744 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 ...
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8answers
3k views

Open source firewall or commercial firewall

In what cases would it be considered OK to use open-source firewalls to protect/secure/filter a company network? There seems to be many open source firewall alternatives (pfSense, smoothwall, ...
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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 ...
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7answers
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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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4answers
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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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7answers
899 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 ...
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2answers
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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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1answer
898 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?
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2answers
445 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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2answers
530 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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1answer
357 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
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1answer
5k 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 ...
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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 ...
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3answers
643 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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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
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2answers
5k 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
931 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
234 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. ...
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3answers
1k views

tunnel over https proxy server (client-server model)

I need to get reliable Internet connection behind a restrictive firewall. facts: firewall handless HTTP CONNECT to anywhere as long as it goes to destination port 443 I have some servers publicly ...
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1answer
816 views

Grant access rights to a MySQL instance based on hostname instead of IP address?

I have a MySQL database that I would like to remotely access from Windows Azure which does not provide fixed IP addresses at this point. Instead of white-listing a very large IP range to cover the ...
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1answer
880 views

Can firewall block packets visible in Wireshark?

Wireshark shows that an RTP package is received on a PC. Is it possible that despite detection by Wireshark, something (firewall?) is still prevent the application listening to the required port on ...
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1answer
19k views

Watchguard Firewall - Issues with SSLVPN

I have a client who has a WatchGuard XTM 23 device on site as their primary firewall. I just upgraded its firmware a couple days ago to the latest version for that series, 11.6.6. The problem is that ...
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1answer
3k views

with ec2, are all internal instances able to connect to each other, or does the security group apply?

Just a little confused, normally a firewall applies to everything externally, and all internal servers (instances) can connect freely with each other. With AWS, it comes with a firewall/security ...
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1answer
1k 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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2answers
154 views

iptables REDIRECT works only for first packet

i need to redirect all UDP packets with destination port 15000 to port 15001 if the packet contains for example the string test. i have these two simple rules: iptables -t nat -A PREROUTING -i eth0 -...
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1answer
448 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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2answers
2k views

iptables command to clear all existing rules

My server is Red Hat Enterprise Linux Server release 5. What is the correct/proper command to clear all existing iptables rules defined in /etc/sysconfig/iptables (so that I can start defining/adding ...
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3answers
1k views

Best Firewall product for hosting/housing environment?

I am searching for a firewall product (appliance or software) for an hosting/housing environment. The biggest problem is that the rules get very complex as more customers are behind the firewall. Some ...
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1answer
273 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 64....
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1answer
464 views

Why did my new iptables rules screw up outbound traffic?

I recently set up Tomcat on Port 80 using instructions provided by Werner Puschitz. In essence, I had to execute these two iptables commands: iptables -t nat -I PREROUTING -p tcp --dport 80 -j ...
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4answers
146 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
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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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0answers
135 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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0answers
805 views

linux firewall + load balance ISP connections

I'm trying to get a linux Mint computer with 4 NIC's to act as a load balance server. The idea is that we have three internet connections, and we want to use all of them so we can share usage of 50 ...
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4answers
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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 ...
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3answers
568 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
4k views

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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3answers
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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
3k 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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1answer
186 views

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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1answer
2k 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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3answers
609 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 ...
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1answer
1k views

Intermittent disconnect: which needs replacing, the router or the modem?

We have a WatchGuard SOHO 6 with the latest firmware (6.4.1) and an ISP-supplied DSL modem. The firebox's PPPoE settings look like this: We've been having a problem lately where our internet ...
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1answer
4k views

IP Table, what does this construct mean ::INPUT ACCEPT [0:0]

I am looking at an IP Table construct, what does the following mean : :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] thanks
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2answers
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I need to create a special rule on my firewall with all the IP addresses from Facebook (Akamai included)… where I can get those IPs? [duplicate]

Possible Duplicate: How to get all IP addresses of a domain? Need this data to create a special rule, and I need to know if they change frequently or not. Somebody told me that they have a ...
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0answers
2k views

windows firewall , some ports not listening

I've added an inbound connection rule for my windows 8 firewall on windows server 2012: I've restarted the Windows Firewall. When I check that port using this program, it says that it is not ...
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2answers
332 views

Can I hook a firewall inside a network and VPN connect to another network?

I'm wondering what I'd have to do to make the following scenario possible: _____________ __________________ | | | | | Network A | | Network ...
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2answers
751 views

Is it safe to ublock 587, SMTP submission port?

We have had problems before with SMTP port 25 (smtp) - some PC's were sending spam mail throught that port. So we blocked that and only allowed only outgoing smtp servers we needed. Howerver, i read ...