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

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-3
votes
1answer
107 views

iptables rules for blocking specific packets [closed]

Im using the following iptables rule: iptables -A INPUT -p tcp -m tcp --tcp-flags PSH,ACK PSH,ACK -m length --length 52 -m state --state ESTABLISHED -j DROP It does it's job for blocking the ...
-7
votes
2answers
847 views

How strong is parallels plesk 11 inbuilt firewall for linux os? from an newbie [closed]

I am new to Linux Dedicated server hosting and plesk panel 11 and i would like to know about inbuilt plesk 11 firewall security features and how harden it is?
14
votes
4answers
3k views

iptables management tools for large scale environment

The environment I'm operating in is a large-scale web hosting operation (several hundred servers under management, almost-all-public addressing, etc -- so anything that talks about managing ADSL links ...
23
votes
6answers
55k views

How to Unban an IP properly with Fail2Ban

I'm using Fail2Ban on a server and I'm wondering how to unban an IP properly. I know I can work with IPTables directly: iptables -D fail2ban-ssh <number> But is there not a way to do it with ...
35
votes
4answers
123k views

Is it possible to change an “Unidentified Network” into a “Home” or “Work” network on Windows 7

I have a problem with Windows 7 RC (7100). I frequently use a crossover network cable on WinXP with static IP addresses to connect to various industrial devices (e.g. robots, pumps, valves or even ...
21
votes
1answer
38k views

What is the difference between a Source NAT, Destination NAT and Masquerading?

What is the difference between a Source NAT, Destination NAT and Masquerading? For example, I thought IP Masqurading was what they used to call it in Linux? But what confuses me is that in our Astaro ...
28
votes
3answers
43k views

Windows equivalent of iptables?

Dumb question: Is there an equivalent of iptables on Windows? Could I install one via cygwin? The real question: how can I accomplish on Windows what I can accomplish via iptables? Just looking for ...
8
votes
11answers
3k views

SOHO - throttle bittorrent traffic from problem users

I manage the network in a small office (SW dev is my "real job"), and there are a couple of users who beat the hell out of our internet connection by running bittorrent. Between the almost crippling ...
11
votes
4answers
3k views

Good 1U Rack Firewall [closed]

I'm trying to find a good 1U rack firewall at a reasonable price. Most pricing is completely out of space (thousands of dollars? Why?). I don't want to list all features I need/want (there are too ...
29
votes
4answers
30k views

What firewall ports need to be open to allow access to external git repositories?

What firewall port(s) need to be open to allow access to external git repositories?
11
votes
8answers
28k views

Blocking Facebook and Myspace by IP address

I'm having some trouble making a Cisco ASA device block certain social networking sites which have become time sinks in our office. This question is really in two parts: Is there a reliable way to ...
12
votes
5answers
17k views

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 ...
9
votes
1answer
15k views

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 ...
3
votes
3answers
3k views

Configuring many block IPs in Windows Firewall

I have a large number of remote IPs to specify in Windows Firewall for a blocking rule. The only way I know to enter them is by labouriously entering them an inbound rule's properties Scope tab. Is ...
2
votes
13answers
11k views

What free options are available for web content filtering? [closed]

I run the IT Dept at a small high school with about 500 users on the network. We have been using SurfControl for this which has been handy because it backs into MS ActiveDirectory very well. We ...
4
votes
2answers
7k views

Reduce firewall rules by half - one iptables rule for tcp and udp

I have a number of iptables rules on my firewall that look like this: iptables -A zone_lan_forward -p tcp -d 1.2.3.0/24 -j ACCEPT iptables -A zone_lan_forward -p udp -d 1.2.3.0/24 -j ACCEPT Is ...
4
votes
3answers
7k 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 ...
3
votes
3answers
3k views

Blocking IP behind a load balancer

Is there any way to block IP address of an intruder (or any IP), when our server is behind a Load balancer. For example if my servers are behind ELB (Amazon ELB) or Rackspace Load balancer, i am ...
3
votes
1answer
1k views

UFW/IPTables: how to securely allow authenticated git access with github

This is how I setup my iptables with UFW: sudo ufw default deny incoming (deny all incoming) sudo ufw default deny outgoing (deny all outgoing) sudo ufw allow out 53 (accept outgoing DNS traffic, ...
3
votes
1answer
3k views

How can I rate limit SSH connections with iptables?

I'm trying to limit the number of possible SSH connections to my server but it just seems to lock me out every time. I'm not very familiar with iptables but I've been reading up on the rules that I ...
2
votes
2answers
1k views

socat connect-connect “proxy” two inbound TCP connections to expose a firewalled service?

I'm struggling a bit trying to see how to use socat (or a similar TCP port redirector) to expose a firewalled service on a PC. Here's the scenario: I have a server PC which will be acting as a ...
2
votes
2answers
2k views

IPFire firewall under Hyper-V. How to get synthetic devices working?

The latest version of IPFire (v2.7 core 38) uses the linux 2.6.32.15 kernel. This includes Microsoft's Hyper-V synthetic drivers. How do I get them working? When IPFire boots, it loads the hv_vmbus ...
2
votes
1answer
17k views

How to configure PFSense firewall with external transparent Squid proxy?

I am using PFSense 2.0 and trying to get transparent proxy to work. As the internal Squid won't work with loadbalancing and dual-wan (and it seems Squid doesn't work at all on the latest build), I ...
1
vote
2answers
4k views

Linux iptables allow some ports

We have a Linux server (CentOS 6.3), where all ports seem to be accessible from inside (when tried from the server), but only SSH is accessible from outside. I would like to allow some other ports, ...
1
vote
4answers
3k views

Linux Firewall + Loadbalancer distribution

Can anyone recommend a Linux specialized distribution (or appliance) which provides both Firewall and Load-balancer? Something similar to IPCop for example, but containing LB as well? Thanks in ...
18
votes
1answer
17k views

What does “!Z” and “!X” mean in a traceroute?

When you see "!Z" or "!X" in a traceroute, what does that mean? Where is it coming from, and how do I fix it?
6
votes
1answer
810 views

Block outgoing connections for certaing uids (root, apache, nobody)

With iptables in CentOS 5 and 6 Linux - how can you please prevent processes running as root, apache or nobody from initiating outgoing connections? On CentOS 5 Linux I've tried putting these lines ...
6
votes
2answers
3k views

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 ...
5
votes
2answers
2k views

Linux fails to interpret ACK, keeps resending SYN+ACK

The following is a wireshark dump of the problem occurring, IP-adresses replaced with 'client' and 'server': 4414.229553 client -> server TCP 62464 > http [SYN] Seq=0 Win=65535 Len=0 MSS=1452 ...
5
votes
4answers
582 views

iptables: change policy or use catch-all rule?

What do you do when setting up iptables: change the default policy (iptables -P INPUT DROP, for example) or add a catch-all rule at the end of the ruleset (iptables -A INPUT DROP)? If you do prefer ...
5
votes
6answers
793 views

Advice a good hardware firewall [closed]

Which firewall would you advice to use to meet following 1Gb line and most anti hacking modules. Price range 10k-15k$. 3 years warranty on site, full support online. About modules, i don't know what ...
4
votes
3answers
5k views

How long does it take for an iptables rule to apply?

How long does it take for an iptables rule to apply? I use a script with the code below in an attempt to block hosts, but they don't appear to take immediately. Is there some delay, is iptables not ...
3
votes
3answers
14k views

Cisco ASA logs “regular translation creation failed for icmp …” for DNS traffic, yet it works

Every few minutes our Cisco ASA 5505 firewall is logging errors that I can't figure out with my limited Cisco experience. Severity Date Time Syslog ID Source IP Destination IP ...
3
votes
5answers
4k views

connect to ssh server thru 80 via HTTP proxy?

Please help: I want to connect to my ssh server at home However, I'm behind a corporate (CORP) firewall, which blocks almost all ports (443, 22, 23 etc). But it seems that 80 is not blocked, coz I ...
3
votes
4answers
7k views

outbound ports that are always open

What are some ports that can NEVER be blocked outbound in firewalls, as doing so will stop basic internet use? Some I can think of are: port 53 udp/tcp -- dns, blocking this will prevent users ...
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 ...
2
votes
3answers
5k views

Ubuntu only allow incoming access from 192.168.0.0/8 or server IP address

How can I make it that only approved IP addresses have access to my Ubuntu server 12.04 I only just set it up.
2
votes
2answers
2k views

UFW/IPTables: after setting default outgoing deny, and port 80 outgoing allow, curl still doesn't work

With UFW, I disabled all outgoing and ingoing traffic by default. However, I do allow port 80 in and out: sudo ufw default deny incoming (deny all incoming) sudo ufw default deny outgoing (deny all ...
2
votes
1answer
7k views

How to make iptables ALLOW rule for multicast?

I have two servers that uses ucarp as failover. On each server eth1:1 is reserved for ucarp's keepalive connection. ucarp uses the destination IP as multicast address 224.0.0.18. On ucarp master ...
2
votes
4answers
937 views

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
votes
4answers
663 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 ...
1
vote
4answers
1k 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 ...
1
vote
2answers
4k 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 ...
1
vote
3answers
300 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
vote
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 ...
1
vote
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: ...
1
vote
4answers
14k views

FTP/SSL in passive mode with portrange, which ports has to be open on the firewall?

We have to use FTP over SSL on our server and use a portrange with 5 ports for the data connection. A firewall is between client and server. We have to know what we have to open at the firewall: port, ...
0
votes
1answer
380 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
votes
2answers
670 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 ...
0
votes
2answers
403 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 ...