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

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0
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1answer
95 views

No response from a remote linux server on specified ports

I have a remote CentOS 6.5 server that is running a tomcat 8 web server (AKA servlet) on port 54321 and I can't access it from my computer, although I'm establishing a successful SSH connection ...
3
votes
2answers
4k views

FTP - 500 I won't open a connection to xx.xx.xx.xx

I'm running a server on AWS and I'm connecting out to a partner's FTP site (not much idea what they are running). My server has an elastic IP. In the results below xx.xx.xx.xx is the internal IP ...
1
vote
0answers
20 views

Synology ssh port receiving too many intrusion attacks, how to ban systematically? [migrated]

I have a synology NAS which I leave at home, and leave it open so I can access it remotely from the office. One of the useful things to do is enable the ssh port so I can access it with my terminal. ...
0
votes
1answer
2k views

Open port 8009/tcp on Fortigate necessary?

A nmap scan of a Fortigate Firewall showed that TCP port 8009 open is. According to knowledge base articles this is only to download the client for ssl vpn. Is this port used for anything else, and if ...
0
votes
0answers
25 views

pfsense routing with dmz wan and sonic wall

Pfsense setup: 2 physical NIC's (1 input from modem/ISP, 1 LAN with a lot of vlans and DMZ) Network setup: WAN block from ISP xxx.xxx.xxx.225/28 Modem -> pfsense -> vlan 40 (192.168.40.0/24) ...
0
votes
2answers
55 views

Ubuntu Iptables Dual Wan - Forward wan 1 & 2 to an internal server

I'm having problems configuring iptables rules on a double wan setup. The OS is Ubuntu 12.04 LTS. I have 2 Wan connections, both with static IP. Wan-1 is on eth2, Wan-2 is on eth4. I want both of ...
2
votes
1answer
29 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 ...
0
votes
1answer
961 views

ZenOSS webinterface connecting

I'm having a problem with ZenOss. I installed the centos stack installer on Centos 5.5 x64. De installation succeeded and no errors where displayed. But when I tried to surft to the ip address it ...
2
votes
4answers
15k views

VPN is working, except for DNS lookups. Firewall (Cisco ASA 5505) issue?

I've got the following set up: LAN -> DHCP / DNS / VPN server (OSX 10.6) -> Cisco ASA 5505 -> WAN Connecting to the LAN via VPN works fine. I get all the details properly and I can ping ...
0
votes
0answers
43 views

ubuntu firewall blocking smtp tasks, port 465 is open

I have been trying to get my Wordpress site able to send emails, and it DOES WORK but only work if I turn off the firewall. I am using UFW. However, I do have port 465 (connecting to gmail) open while ...
0
votes
1answer
76 views

WatchGuard blocking internal UDP packets

I'm seeing lots of packets that our WatchGuard firewall is dropping. They're all hitting either 255.255.255.255. or 224.0.0.1 using UDP 8612 / 1947 / 17500. Since I've started seeing these messages ...
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votes
2answers
41 views

IPTables not blocking IPStresser [closed]

I have been trying four days to block DDoS attacks with no success. I want to block anything that isn't whitelisted. This is my idea on OS Centos 7: //Delete All Existing Rules iptables --flush ...
0
votes
1answer
859 views

How to unblock service discovery for IPv4 via Avahi?

On a Debian 6.0.6 system (squeeze) I am having trouble resolving a host using Avahi and IPv4. Here is a sample output: : nr@homedog 10102 ; avahi-browse -a + eth0 IPv6 yorkie [00:1f:3b:d8:67:1d] ...
-1
votes
1answer
41 views

Multiple Gateways on LAN

This is more a theoretical question. Let's assume we have a Firewall/DG (with a connected WAN) on LAN IP 192.168.1.1. All external DNS records for incoming services like OWA, FTP etc. point to this ...
1
vote
1answer
919 views

Amazon EC2 Socket connection not being accepted

I am trying to run a java application on my EC2 instance. The application accepts socket connections on port 54321. If I try and connect to it, it times out. My Security Group is set as: TCP Port ...
0
votes
7answers
9k views

Advice for configuring a SonicWALL NSA 2400 to use two subnets and L2 Bridge Mode

This post is not an exact duplicate of How to configure remote access to multiple subnets behind a SonicWALL NSA 2400 . However, I am having this problem, almost verbatim. Unfortunately, we even have ...
0
votes
1answer
1k views

Allow access to printer between interfaces on Cisco ASA5510

I have a Cisco ASA5510 where we have to separate networks on two separate interfaces. The networks should have nothing to do with each other except that network B needs to access a printer on network ...
2
votes
2answers
3k views

Configuring Fortigate OS4 for FTPS

I configured iis7 ftp to allow ssl connections. I set the ssl firewall to use ports 50000-50050. If I set up a custom service on my fortigate firewall for ftps with source ports 990-50050 and ...
0
votes
2answers
1k views

Access print server through firewall?

At my workplace, we have two fiber networks setup, one for the business network and the other for process control (industrial manufacturing). On the business network, there is a standard print server ...
2
votes
2answers
1k views

Cisco ASA 5505 Config

I have looked through a lot of these posts on the Cisco ASA5505 as well as gone online. I am looking for some straight forward step by step instructions to complete the following tasks. I know how to ...
0
votes
1answer
24 views

Web app architecture - firewall blocking

I'm currently working on a web app and seem to be having a few problems with the app being blocked by office firewalls of our test groups. My background is in design / front end so my knowledge of ...
0
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0answers
14 views

Sonicwall seems to be blocking port 3690 on random internal up address

We are trying to connect to a clients subversion server over the internet using port 3690 and random internal ip address are getting blocked and time out all of a sudden. My local ip of 192.168.0.150 ...
0
votes
2answers
45 views

How to restrict outbound EC2 to only access S3?

I want to restrict the outbound security group from an EC2 instance. The instance only needs to access an S3 bucket. I just learned that S3 uses port HTTPS (443). I could just put that rule in place ...
0
votes
0answers
30 views

Network configuration for Virtual machine based firewall

I have this physical configuration: And I'm planning to install IPFire (or similar firewall : pfSense or Sophos UTM) on a virtual machine on the Active Directory Server to control traffic between ...
1
vote
1answer
5k views

Handshake violation when trying to access one website

I have a TZ 190 Wireless Enhanced with SonicOS Enhanced 4.2.1.0-20e. Yesterday, people could access without any problems a bank website wich uses HTTPS. Today, it is imposible to access only that ...
0
votes
0answers
24 views

Windows Advanced Firewall - Advanced Rules? [duplicate]

my game server is being DDoS attacked (Windows Server 2012). Probably you would say there is nothing I can do but I don't think so because I can use my dedicated server in a normal way, it's just that ...
0
votes
1answer
2k views

Iptable l7-filter installation guide and block p2p

I would install l7-filter to block P2P torrent, First of all , I have a linux debian. I installed by the below command apt-get install l7-filter-userspace And then run command iptables -I FORWARD ...
1
vote
2answers
1k views

Smoothwall Express interface issues

I have a SmoothWall Express box that is currently configured with a Green and Purple interface. Both interfaces are in the same /24 subnet (which seems odd to me). The green interface (address of ...
-4
votes
1answer
64 views

How to open Port 443 on External Firewall? [closed]

I've been trying to configure SSL on my server for last 4 days now, with absolutely no success. I've generated a CSR file and uploaded the certificate and configured a Vhost, but nothing seems to ...
0
votes
2answers
12k views

Fortigate 200A firewall CPU high resource usage

This morning I'm receiving complaints from several end users that saying their whole department network are slow and have intermittent. Therefore I've checked our firewall to see whether if something ...
1
vote
2answers
32 views

Does Windows Network Load Balancing require any specific ports to be open?

I have two Windows 2012 servers, joined in a Windows Network Load Balancing cluster. I have been trying to find how the NLB heartbeat message is exchanged between those servers (to make sure it will ...
1
vote
1answer
51 views

Apache problems in performance test with mod_reqtimeout

We have 2 Apache webserver behind a load balancer wich are connected to 2 (JBoss) application servers via mod ajp. To those webservers, mobile devices connect via a REST API. In our performance ...
0
votes
1answer
34 views

Loading fail2ban rules to iptables using iptables-persistent

I am using iptables-persistent package to reload my iptables on boot. And I have been thinking should I add the fail2ban rules to the loaded config file? Now I am seeing they are duplicated. This is ...
1
vote
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 ...
0
votes
2answers
76 views

How to enable CentOS 7 to connect to an external SMTP? [closed]

I have a web application deployed in a webserver, running on a CentOS 7. This web application sends e-mails through an external SMTP (in-v3.mailjet.com, port 587). How can I enable CentOS to connect ...
17
votes
1answer
15k 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?
-1
votes
1answer
38 views

Open source firewall as a virtual appliance? [closed]

Is it possible to have an open source firewall which can run as a virtual appliance into a guest VM where all traffic from the other VMs should go through this firewall VM? And it supports also ...
-1
votes
1answer
45 views

Block everything except some ports and specific IP Addresses, server can't do HTTP GET

I can't get this firewall.sh script to work. It currently doesn't allow me to get a file at 'https://index.docker.io/v1/repositories/library/ubuntu/images' so either my DNS is flawed or I am blocking ...
0
votes
2answers
493 views

Nginx, ModSecurity, IP Tables blocking WordPress dos/ddos attack

For the past 14 days I have had my website being hit by millions of WordPress installs over the world which .htaccess is kind of coping with but I am trying to get something to kick them before ...
1
vote
3answers
1k views

Configuring Iptables On CentOS 6 Locks Me Out

I'm running the following bash script as root to configure iptables (I'm logged in via SSH): #!/bin/bash # Delete all existing rules iptables --flush # Set default chain policies iptables -P INPUT ...
1
vote
0answers
30 views

Hadoop namenode port getting blocked

I have installed 7 VM instances of Ubuntu 14.04 LTS servers. First instance runs the namenode service and all other 6 nodes run datanode service.I think my NameNode is getting crashed or blocked due ...
-1
votes
2answers
35 views

Is there a way to block ALL inbound/outbound traffic going outside of a LAN with iptables?

As the title says, I'm just looking for a way to disallow any traffic on ANY port unless it's going to a local IP address (192.168.1.*).
0
votes
1answer
42 views

How can I adapt this technique of using a proxy (in firefox) to wget and yum ? [closed]

I work in a large organization where some people have extremely restricted internet access and some are given a fairly large amount of freedom. The way my organization manages this is by running a ...
19
votes
7answers
102k views

What firewall ports do I need to open when using FTPS?

I need to access an ftps server (vsftpd) on a vendor's site. The vendor has a firewall in front of the ftps server and I have a firewall in front of my ftps client. I understand that ports 990, 991 ...
40
votes
15answers
16k views

iptables Tips & Tricks

I'm sure Linux sysadmins are quite familiar with iptables, the userland interface to the netfilter packet-filtering framework. Now, this "Question" is meant to be a Community Wiki for collecting ...
-1
votes
1answer
70 views

How to allow google-analytics via iptables when internet is blocked for other traffic [duplicate]

I am running the following script on a wifi gateway. The WAN side of the gateway has ppp0 interface while LAN side is on wlan0. No LAN user should be allowed to browser internet Some services on ...
9
votes
3answers
41k views

CentOS 7 Firewall Configuration

In CentOS 6 I could type setup from the command line and I would be presented with a set of tools, one of them being Firewall configuration. I can still do this in CentOS 7, except the list no longer ...
0
votes
0answers
25 views

pfSense WAN load balancing across two IPs (has single gateway)

My virtual setup has two IPs, but they rely on the same gateway. I had this configured: interface - type - IP address - Gateway em0 - WAN1 - 172.16.155.131 - 172.16.155.2 em1 - LAN ...
0
votes
1answer
295 views

MikroTik - can't access webfig from external / can't SSH into router from external ip

Ok, here's the deal. Let's say that my public facing IP is 10.0.01. I can't webfig into 10.0.01 from external and can't SSH into mikrotik router from external IP. I can do it if I am physically ...
-1
votes
1answer
22 views

SSH port blocked EC2

I had installed Tomcat on my EC2 instance . However i was unable to access it using my public IP:8080 . So I followed the instructions mentioned in the post ...