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

learn more… | top users | synonyms

4
votes
3answers
3k views

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 ...
4
votes
5answers
401 views

recommend firewall options for a dedicated server

I'm looking for recommendations on firewalls for a dedicated server that will be hosting a few websites of average traffic (5000 uniques monthly). the hosting company has port and full hardware ...
4
votes
5answers
773 views

Is it beneficial to chain multiple firewalls at the perimeter?

I'm currently running ISA 2004 and will soon be running an Untangle box. I've always felt a tiny bit safer putting these more advanced software firewalls behind a dumb hardware firewall (like ...
4
votes
1answer
11k views

Which firewall ports do I need to open in order for a domain trust to work?

I have two Active Directory domains in two different forests; each domain has two DCs (all of them Windows Server 2008 R2). The domains are also in different networks, with a firewall connecting them. ...
4
votes
3answers
918 views

Can our firewall detect traffic sniffing inside the network?

We use Cisco ASA's firewall and NAT functions in our network (200 computers). Is there any possibility to configure Cisco ASA to detect traffic sniffering (for example wireshark) and network ...
4
votes
3answers
7k views

Denying ICMP type 3 code 4 traffic - good or bad?

Investigating a slow VPN connection (Cisco ASA IPSec) to a remote office, I noticed on our firewall a lot of access rule matches: Denied ICMP type=3, code=4 from *ip_address* on interface outside I ...
4
votes
1answer
5k views

DMZ Setup with two firewalls - Traffic from DMZ to LAN and LAN to DMZ

I am setting up a network with machines that need to be accessible from the internet. I'm planning on putting these in a DMZ. Some of the machines in the DMZ need access to machines on the private ...
4
votes
2answers
6k views

Should I rate-limit packets with iptables?

I'm using iptables on Ubuntu Server. It's a web server on a VPS. I'd like to know if I should rate-limit packets. If so, what should I rate-limit? And should I do so globally or per IP address? ...
4
votes
1answer
222 views

Can tcpdump tell accessed port numbers?

I have a server with two NICs, and I would like to only have those ports open on eth1 that are being used. Question How do I get tcpdump to tell me the port numbers that is being accessed on eth1?
4
votes
3answers
315 views

node.js 0.4.0 not serving files to external IPs

When I run the following script http = require('http'); http.createServer(function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World\n'); }).listen(80, ...
4
votes
3answers
3k views

MSMQ Firewall Ports

I'd like to know what ports need to be opened on a firewall in order to allow public read access to an MSMQ private queue. I'm aware that Microsoft publishes a list of ports here: ...
4
votes
1answer
544 views

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 ...
4
votes
3answers
986 views

connected to Centos openvpn but no outside internet access

I am using Windows 7 to connect to a VPS server running CentOS 6.4 First off, I have read every single post and just cant find the solution to my problem I configured my VPN server with openvpn, and ...
4
votes
2answers
179 views

ipv6 multiple addresses and firewall on remote machine

I have an ubuntu server (serverA) which has a couple of IPv6 addresses. One of these is based on it's MAC address, and is known to the network, the other one I presume ubuntu created as a 'private' ...
4
votes
2answers
3k views

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 ...
4
votes
2answers
4k views

How can I track down what part of pfsense is blocking website access?

I've got a PFSense firewall/gateway on our network. Everything works great except for the fact that I cannot access one specific website. Pfsense is running the following packages Country Block ...
4
votes
2answers
538 views

Iptables - Block https response only

I'm quite new to Linux and using iptables. Here is what I am trying to accomplish: I have an ASP.net client that talks with a web service hosted through web-logic on linux. The communication is over ...
4
votes
1answer
469 views

Block outgoing LOIC attacks in a network

I am admin of a small network. Users in our network have access to internet through a squid NAT server. Recently, we have detected that some users are using LOIC to attack servers on the internet. ...
4
votes
5answers
238 views

What are the 'gotcha's' a software developer needs to look out for if tasked with setting up a production ready server?

As a software developer I am very used to installing my typical stack (java, mysql and tomcat/apache) on my development machine. But setting up and securing a production machine is not something I ...
4
votes
3answers
21k views

How can I open a port on my EC2 instance?

I'm working for a client here who has set up an EC2 instance for me to configure. I've installed the software asked for, now all I need to do is open up some ports. I'm currently SSH'd into the ...
4
votes
3answers
186 views

linux Firewall question

I have few generic questions about firewalls and I thought the community up here could help me out. 1) So I recently installed Ubuntu server barebones. I checked for open ports, none were open which ...
4
votes
2answers
903 views

iptables and blocking potentially impossible traffic

I am working on some iptables firewall rules and have seen many examples that suggest the importance of blocking potentially impossible traffic from non-routable IP address spaces. This would include ...
4
votes
4answers
594 views

Why on linux machines, any packets do not pass except icmp, but correctly pass on windows

There is a cluster on proxmox. In a cluster have vm - configured router (pfsense). In the our net have Windows and Linux machines. There is the problem: Windows-machines have access to the internet, ...
4
votes
1answer
106 views

Managing security and firewalls in complex, distributed applications

We have a distributed application composed of several different components. For example, we have Python app servers, PostgreSQL DB servers, Redis servers, Memcached, etc. Some of these services are ...
4
votes
1answer
675 views

Firewall ACL management tool

Is there any Firewall ACL management tool which can generate set of ACLs for all my network, including switches, checkpoint, cisco routers, windows, linux etc? I think such tool would make sense as ...
4
votes
1answer
99 views

Seeing strange IPv6 requests being dropped in our firewall

I'm seeing the following IPv6 addresses having requests dropped by our firewall. It doesn't seem to be anything too malicious, but there seems to be a strange pattern to them: ...
4
votes
1answer
1k views

Cannot loopback to localhost php gateway causing nginx to timeout while setting up firewall with ufw

I'm setting up ufw for the first time. Using Ubuntu 10.04 LTS on an OpenVZ VPN and have the following rules: sudo ufw allow 22/tcp sudo ufw allow 25/tcp sudo ufw allow 53 sudo ufw allow 80 sudo ufw ...
4
votes
3answers
6k views

How to configure remote access to multiple subnets behind a SonicWALL NSA 2400

I have a client that uses a SonicWALL NSA 2400 as their firewall. I need to setup a second LAN subnet for a handful of PC. Management has decided that there should be a second subnet even though ...
4
votes
3answers
2k views

OWA not working from outside the network

I have an Exchange server behind an ISA 2004 server and from inside the network, it's possible to access Outlook Web Access. I have published the server but from outside the network I'm not even ...
4
votes
1answer
100 views

firewall and private cloud

We have a private bay in which we built a private cloud with vmware vSphere. We received directly the web trafic on a firewall VM and then we forward the trafic to the appropriate VMs. We are worry ...
4
votes
1answer
118 views

Ban an IP when the server received an amount of data from it

What I need : There are many result for adding a drop rules by an amount of request per laps of time, but I need to drop by received byte count from a particular address over a period of time. ...
4
votes
2answers
123 views

iptables - allow connections to a port only for IP addresses with established state on a different port

I want to allow connections on port x for IP addresses that have a 'established' state on port y. Is this doable by just using iptables?
4
votes
1answer
447 views

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 ...
4
votes
3answers
5k views

automatically block IP address after many failed login attempts

I am receiving a lot of failed login attempts (1 per sec) on a Windows 2008 server, I have already set local security policy to automatically lock an account after too many login attempts, but is ...
4
votes
3answers
6k views

pfsense log file retention

We have a pfSense firewall in our datacentre. By default, pfSense is only storing 500K of firewall filter logs, which is only a few hours for us. How can I increase this? pfSense uses clog rather ...
4
votes
3answers
8k views

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 ...
4
votes
7answers
26k views

problem with passive FTP behind cisco asa firewall

i've problems connecting to an ftp-server behind a cisco asa firewall using passive mode. ftp works using active and "extended passive" mode, however: when i turn off "extended passive" (epsv in ftp ...
4
votes
1answer
542 views

Why does Terminal Services open WMI, RPC, and NB ports in the firewall?

After adding the Remote Desktop Session Host roll to a server the following firewall rules get created and are enabled by default. Name Group Profile ...
4
votes
1answer
525 views

ipset - recommended method to reload rules after reboot

Am implementing ipset on some Fedora 16 systems. Since ipset rules run in memory and are lost on reboot planning to use a crontab @reboot script to reload the rules and send an email to administrator ...
4
votes
1answer
17k views

How do I route between interfaces in PFsense?

I have a PFsense router which divides a single WAN connection into three NAT networks on three interfaces: LAN, OPT1 and OPT2. This allows me to segregate my network so that computers on the OPT1 and ...
4
votes
1answer
3k views

Single m0n0wall - Two LAN Subnets - How To Setup

I have two LAN subnets that I need to link together they are 192.168.4.0/24 and 192.168.5.0/24 There is a m0n0wall running on 192.168.4.1. It's LAN connection goes out to our network switch, and it's ...
4
votes
2answers
3k views

Correctly setting up UFW on Ubuntu Server 10 LTS which has Nginx, FastCGI and MySQL?

I'm wanting to get my firewall on my new webserver to be as secure as it needs to be. After I did research for iptables, I came across UFW (Uncomplicated FireWall). This looks like a better way for me ...
4
votes
2answers
251 views

Windows XP firewall behavior mysteriously changed

Recently (July 13, 2010) I had a firewall rule that started blocking traffic that had previously been allowed. I have an FTP server running on a non-standard port serving files to the LAN. I had ...
3
votes
9answers
5k views

Why am I Unable to ping port 443 on Ubuntu?

I have opened port 443 through iptables: pkts bytes target prot opt in out source destination 45 2428 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0 6 1009 ACCEPT tcp -- * * 0.0.0.0/0 ...
3
votes
7answers
3k views

Stealthed vs Closed Port

I was reading a website about the difference between stealthed and closed ports. http://www.grc.com/faq-shieldsup.htm A closed port will echo a packet if closed. However, a stealthed port will not ...
3
votes
7answers
2k views

Good linux firewall? [closed]

I am looking for a good firewall for debian 5 which is a web server. Are there any good options apart from iptables? Thanks
3
votes
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
votes
9answers
22k views

“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 ...
3
votes
8answers
41k views

How to enable sshd on Fedora 11?

I have just installed Fedora 11 on my desktop system and would like to have sshd work. These are the steps I have done: Enabled sshd as a trusted service using system-config-firewall Restarted sshd ...
3
votes
5answers
215 views

Good firewall for Vista? [closed]

I just bought my first laptop. It runs Vista, and I need a software firewall to protect both its Ethernet and wifi connections. I use the free Comodo Personal Firewall on my desktop, but I read that ...