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

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Allowing services to specific hosts using firewalld

Introduction On my database server (CentOS 7) I want to allow access to port 3306 (MySQL) from specific web front-ends (10.10.40.6 and 10.10.40.7 in my example). On top of that I want to allow access ...
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10 views

Cisco 5512-x TCP request discarded

We have a fairly basic ACL and NAT rule allowing RDP inbound and NAT'd to a LAN IP (all IPs replaced with IP) object network STATIC-PAT-RDP host IP access-list outside_access_in extended permit ...
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1answer
45 views

Allow only SSH, FTP and Cloudflare Servers via IPTables

I want to allow only SSH access, FTP access and all communications between my Dedicated Server and all Cloudflare Servers using IPTables. I tried the commands beneath but it seems like I kicked out ...
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1answer
27 views

FreeBSD pf with NFS

I'm having trouble establishing new NFS connections when my pf is turned on. When I turn off pf on the server and client I'm able to mount with no trouble. I tried keep state and flags S/SA on the ...
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26 views

Making the server communicate only with cloudflare IP`s [on hold]

I bought a new Server at OVH, after we got kicked by our old data centre to our DDoS. I want to setup the firewall correctly, which only allows communication with cloudflare servers, but I am not sure ...
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30 views

SPAMMERS and DNS attacks [on hold]

I am having a few small issues with a number of IP ADDRESSES that seem to keep trying to access the server. I am wondering is there any software for CentOS which is like an auto IP Blocker which is ...
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1answer
38 views

iptables block net range

I'm trying to REJECT network via iptables(8) and for whatever reason it is not doing so: # cat /etc/redhat-release Red Hat Enterprise Linux Server release 6.6 (Santiago) # uname -a Linux X ...
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10 views

What would cause pysmb to fail when OSX Finder “Connect to Server…” succeeds? [migrated]

(originally asked on StackOverflow, but I think there are more appropriate experts here): I'm trying to transfer a file from a remote samba share (on a windows server) in a python script (running on ...
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1answer
26 views

Identify individuals behind SLAAC addresses

We're operating an IPv4 network (on ethernet & Wifi) in a student dorm with ~200 users and want to deploy IPv6 in the long term, with stateless autoconfiguration on a single /64 prefix. ...
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22 views

How to configure cisco asa nat with an internal router? [closed]

I need to configure nat on a private host that is on a remote location/network other than the private network of the Cisco ASA. Cisco ASA is at HQ with 172.10.10.0 private network and private host is ...
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0answers
17 views

A service like a router between 2 WAFs. This exists?

A service like a router between 2 WAFs. This exists? I have the following situation: 2 different WAFs (CloudFlare and Incapsula) and would like to have a service above the two that I can define ...
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5 views

firewalld allow connections to a port for only a subnet of IPs [duplicate]

I am on Fedora 21 Workstation on my PC. By default, all ports through firewalld are open on Fedora 21. When I open a service accessible through a port (such as a CouchDB or a SQL server or a simple ...
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1answer
44 views

How to test iptables settings by port scanning?

I want to test my iptables and prove that it only allows traffic for given Protocol / Port - combinations. How I can use as a target for a port scan?
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1answer
42 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
81 views

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 ...
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35 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
16 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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1answer
12 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
57 views

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

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
19 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
38 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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5answers
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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
25 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
91 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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2answers
80 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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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
57 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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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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1answer
21 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
60 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
160 views

Iptables rules with ! character

I have entered iptables rules to log a specific connection on our server, but it doesn't seem to be working as I want it to. Here are the rules: 1 LOG tcp -- !10.51.0.0/16 ...
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1answer
32 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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22 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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1answer
53 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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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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0answers
27 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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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 ...
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9 views

Open ports in firewall on Cisco SRP500 Series?

I have a Cisco SRP527W. I cannot work out how to open ports in the firewall for all machines. In the past, I port forwarded to the server, but now I just want a port open to all users of the network. ...
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2answers
43 views

How do I drop requests from dig?

Basically I'm getting tons of request to my named/bind service, basically those requests are being rejected by named, Those are the messages i get, from tons of ips., How extacly can I drop those ...
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9 views

Block ICMP flood from a specific IP with pf [migrated]

I'm getting a lot of ICMP throttle messages in my system.log: Apr 11 20:45:28 kernel[0]: Limiting icmp unreach response from 1054 to 250 packets per second Apr 11 20:45:29 kernel[0]: Limiting icmp ...
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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. ...
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36 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) ...
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1answer
113 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 ...
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2answers
74 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
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1answer
46 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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56 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 ...
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2answers
46 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 ...
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4answers
138 views

Cisco ASA Implicit rule dropping traffic

The network is as follows: Two Default Gateways exist on the network - one which provides connectivity to the an MPLS with several subnets. Let's say 10.0.0.2 Another which is a Cisco Firewall, on ...
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1answer
43 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 ...
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1answer
25 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 ...