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

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Chinese Firewall DDoS and IPtables not working

Recently my server has been hit with DDoS's coming from the Great Chinese Firewall. As per the advice in one of the replies in mod_security block requests by http-host header, and the advice in ...
2
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1answer
25 views

Yes-sayer as a target for port scanning

I want to test my iptables and prove that it only allows traffic for given Protocol / Port - combinations. Is there a tool that I can use as a target for a nmap port scan?
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1answer
28 views

Port 8080 remains closed even when opened with iptable and nodejs is listening on it [duplicate]

I am trying to install a nodejs server listening to port 8080 that I opened with iptable but when I run nmap or a web tools I always get the message that the port is closed. I'm on a Ubuntu vps. ...
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1answer
1k views

QoS settings for Wi-Fi calling on pfSense firewall/gateway?

The new version of iOS 8 as well as Android supports Wi-Fi Calling with multiple cellular providers including T-Mobile in the US. I am currently running pfSense as the primary Internet gateway for ...
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3answers
58 views

Assign IPs to programs/processes

I need to assign different IP addresses to different processes (mostly PHP & Ruby programs) running on my Linux server. They will be making queries to various servers, including the situation ...
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0answers
23 views

IPTABLES and GEOIP: Show Custom Webpage to Blocked Visitors

Because of legal protection, as a first stage of launching my project I will focus on couple of countries only. The number of supported countries will grow. I know, it is possible to block or allow ...
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1answer
907 views

Should I create a second WAN Interface for a new SSLVPN setup on my Sonicwall 2400?

Sonic Wall 2400 I'm setting up a new SSLVPN on our Sonicwall, very new to this. I currently have an exchange server as well, so mail.company.com is directed to our mail server. I'd like to setup a ...
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1answer
992 views

iptables denies internal access to port 17500

In the kernel log there are hundreds of these lines. The source is the external IP of the VPS (not localhost nor 127.0.0.1), other times an IP of the network of the VPS provider. The source port and ...
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1answer
13 views

Do I need to set rules for source and destination ports for outgoing rules on iptables?

I'm using puppetlabs firewall module and I'm having troubles setting up iptables for a simple web host. I'm following this guide and want to set up additional rules. ...
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4answers
1k views

apply back firewall after iptables flush

yesterday i got my self locked from my own server. and than i try to flush iptables from another server to get it unlocked as this question response 3 times fail then lock After that, i cannot login ...
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5answers
6k views

I accidentaly forbid SSH connection to a remote server… What's next?

Let's say it again, we all make mistakes, and I have just made one. A brief history: I was doing some stuff on a VPS (Debian) I'm renting, when I noticed some strange behaviour. Using the netstat ...
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1answer
10 views

Concurrent connections per IP

I need to make a few changes to a firewall configuration, but before I do I'd like to see the number of concurrent Apache connections per IP. This command produces a nice list: #netstat -ntu | awk ...
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3answers
54 views

How I can Block all China to entry to my server [on hold]

How I can Block China to entry to my server ? All China country ? By ipset and iptables I want by this to avoid DDOS attacks OS: CentOS 6.6 Thanks.
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1answer
295 views

Cisco ASA 5500 — List of outbound connections?

Is there a command or GUI option to get a list of outbound connections. Ideally, I'd like to know the internal IP address, the external IP address, and the remote port used. I don't need a lot of ...
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1answer
659 views

How can I protect my website with cisco ASA Firewall 5520 and do url and web filtering?

I've got a cisco ASA firewall 5520 on my small organization's network, and i'm quite new to ASAs as i have just finished my SNAF course and need time and experience. My question is how can i protect ...
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1answer
17 views

Does Sophos firewall support outgoing FTPS connections?

Is it possible to connect through a Sophos firewall to an external FTPS server? With FileZilla and connection mode "Require explicit FTP over TLS", the log shows: Status: Connecting to x.x.x.x:21... ...
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0answers
27 views

Iptables content blocking firewall

I have setup a firewall with iptables to ratelimit connections based on content. The following is an example of one of my rules that stops wordpress bruteforce attacks. `iptables -A INPUT -p tcp -m ...
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2answers
50 views

How to open port for a specific IP address with firewall-cmd on CentOS?

I would like to open port 4567 for the IP address 1.2.3.4 with the firewall-cmd command on a CentOS 7.1 server. How can I achieve this, as the documentation I could find was too specific on this?
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1answer
18 views

Load average increasing along with firewall throughput

I've just pushed a large change to my backend code and I've noticed a massive increase in the load average in the few hours since the push. I looked at Munin for what the problem might be and I ...
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2answers
41 views

iptables block client ip internet access and keep LAN access

With the increase of appliances having network access and the potential for hacking, I want to block specific ip address from accessing the internet, but allow LAN access. For instance, I use a ...
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1answer
68 views

Linux - show dropped packets form firewall

I am trying to set up a sip trunk and so far everything has gone well. The only issue I face is that the call does is not received when the iptables service is running. By stopping the service ...
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0answers
12 views

Route traffic to internal device on local address for internal clients

There is no DNS server at the site, so the URL is always resolved to an external address on the Firewall. Hence traffic originates on the local network, goes out the firewall and cannot connect to the ...
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3answers
41 views

Why can i not ping my host behind the firewall. Cisco asa 5505 [closed]

Can anyone please help me to figure out what in my configuration of the Cisco asa 5505 is wrong or missing. I have multiple host behind my firewall these hosts run different websites on port 80. I am ...
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3answers
4k views

WMI: How can I fix the port?

I need to use WMI for getting some information from my servers. But I have a server in DMZ, so I need to open a port in my firewall. I've searching and I found that WMI uses random port. How can this ...
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2answers
50 views

Resolve external DNS entries conditionally by request network source [closed]

I recently set up Sophos UTM as public firewall/ALG which I use for all kinds of things, such as VPN server, reverse proxy. When I tried configuring the DNS for my external domains, I had to notice ...
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1answer
3k views

Watchguard config, drop-in or mixed-routing mode?

I have a Watchguard XTM 2 that is currently acting as a firewall and a router for my business network, I currently have the WG setup in mixed-routing mode and am happy with the current configuration. ...
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1answer
24 views

Is the use of the RELATED state in iptables used properly?

I have been seeing many people using the ESTABLISHED and RELATED flags together to ACCEPT traffic through once a connection was previously accepted (see Allowing Established Sessions). Say I setup my ...
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2answers
605 views

How to make an existing caching Nginx proxy use another proxy to bypass a firewall?

My question is about using Nginx as a proxy behind another proxy. (Somewhat confusing.) I want to set up Nginx so it acts as a caching proxy server to an npm mirror. Here is the link: ...
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2answers
1k views

Routing between multiple Mikrotik Firewalls

I have 2 Miktorik RouterBoards, an RB1100 and a RB951G. The 951G is acting as my Wireless box, and has Guest, Internal and Internet Only Wireless networks. The RB1100 has 3 WAN connections (2x150/10Mb ...
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1answer
19 views

Using two openvpn clients to expose services of a server

I am currently attempting to use two openvpn clients to expose services of a server, as is already said in the title. I may be playing with powers far beyond my current comprehension, but please bear ...
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1answer
34 views

How to enable firewall on Centos 7?

My firewall is currently inactive. systemctl status firewalld firewalld.service Loaded: masked (/dev/null) Active: inactive (dead) I used the following command to enable the firewall # systemctl ...
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3answers
3k views

Configure multiple lan interfaces for same subnet on sonicwall

We have a sonicwall 2400, Is there any way to assign multiple interfaces to the same lan subnet? Basically, we would like to have X1 for the wan and X0, X2, X3 and X4 connected to 4 devices that would ...
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1answer
39 views

Nmap external scan shows port open, ASA says port is not open, but do get an socket

Folks, have a weird one, need your expert help. For one of our heavily used external facing server which came up in an audit, nmap -Pn scan shows the following: Starting Nmap 5.51 ... Host ...
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0answers
872 views

cisco asa reloading

After having both memory and code upgrades, we have a significant number of our asa 5520's (in active/standby pairs) develop problems. The problem manifests itself as losing connectivity to the other ...
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1answer
27 views

How to setup monitoring of nodes behind firewall

As lame as it may sound: I am trying to configure monitoring for our production system which consists of 2 hardware boxes with ESXi on both and multiple VMs. All of this is hidden behind a firewall ...
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1answer
29 views

How do I use CSF to redirect domain requests to a port?

I have a server setup that uses two different webservers with different subdomains. Right now the servers listen on different ports (80 & 4000) So users don't have to put in :4000 I'd like to ...
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0answers
20 views

Remote packet capturing using fifo and dumpcap

I'm currently working on two linux servers where one server is running in 2.6.18-274.el5(Server A) and the second one in CentOS 7 (Server B). My requirement is to capture the packets of the network ...
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3answers
2k views

Sonicwall NSA2400 - No internet access

We've got a SonicWall NSA2400 configured with a LAN (X0) and a WAN(X1) interface. It was setup and working fine until just recently when a temporary worker changed some settings most likely NAT. We ...
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1answer
7k views

PPTP connection fails with errors 800/806

I've got a client (Server 2008 R2) that won't connect to our production environment PPTP VPN server (Server 2003, running RRAS). The server is behind a firewall that has TCP1723 open as well as GRE. ...
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1answer
940 views

Ubuntu 12.04 open port 80 inside VLAN

I have an nginx server running on ubuntu 12.04 that serves http through port 80 and https through port 443. Everything works fine if I access it from the same computer via localhost, 127.0.0.1 or the ...
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2answers
1k views

KVM: All network traffic to one guest (firewall)

I am currently using a VMWare ESXi 5.5 server for my virtualisation. The network setup is like this: PFSense firewall is the center of it all and connected to: LAN Network (physical NIC 1 assigned by ...
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0answers
10 views

Firebox x700 Reset to Default Not Working

I found a site that explains how to reset a Firebox 700 series back to default as you can see from this link: https://www.hashdoc.com/documents/7502/how-to-default-a-watchguard-firebox-700-or-x700 ...
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4answers
1k views

Server not reachable on all TCP ports from all locations

I have a very strange situation on a Linux (CentOS) server. Firstly, from my Ubuntu desktop PC, I can successfully connect to all services that are running on it, on ports 22, 80, 8080 and others. ...
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1answer
146 views

OpenStack FWaaS extension

According to the OpenStack API documentation, OpenStack now provides APIs to manage and deploy firewalls to protect the networks. The information available for the firewalls via the APIs seems very ...
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0answers
26 views

Solving an asymetric HA Firewall/router

I have an old Linux HA firewall/router setup that never quite worked. As it was never quite put into true production (just testing and demo's), I always had to have one firewall shutdown to make it ...
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3answers
1k views

Limit UDP connections per IP iptables

I want to limit connections per IP for a specific UDP port. I got it working for TCP, but somehow it doesn't work on UDP. These are my rules: For TCP (working) iptables -A INPUT -p tcp --syn ...
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4answers
1k views

How to block ALL communications with an IP-address using iptables?

I have a FreeBSD system behind a Linux-based router (using DD-WRT firmware). The FreeBSD system is running sshd and is regularly probed by various script-kiddies. It currently runs a script, that, ...
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2answers
2k views

Iptables - Allowing only a single dhcp (relay) client

I am trying to create a firewall rule on an Ubuntu 10.04 server running isc-dhcpd. I only want dhcp to be accessible by a single relay host (172.1.1.1). I have iptables set up like so: # iptables ...
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2answers
2k views

Juniper SSG5 DHCP IP Pool is full. Unable to offer IP address to client

hope we have some Juniper guys around, I have configured a Juniper SSG5 as our main firewall/router the DHCP server set on interface bgroup1 to have a rang from 10.10.10.76 to 10.10.10.210 All ...
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0answers
17 views

iptables, after specifying an interface to drop traffic it drops all traffic of all interfaces

We have currently the situation that one interface (eth0) is linked to the internet. and we 2 other devices (eth1/eth2) for management purposes. Now the idea is to block off eth0 completely from the ...