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Questions tagged [firewall]

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

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Firewall block all but one ip spoofing

We have a server which accepts traffic coming from a few sources (ip addresses) and accept's it (using firewalld). All other traffic inbound is blocked. How likely is the risk that somebody ...
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Can firewall rules be applied to internal GCLB?

tl;dr We're experiencing issues with services behind internal Google Cloud Load Balancer not being able to reply when response is over a certain size. Upon some tcpdump'ing and wireshark'ing, it ...
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Two similar services, two IPs, one server?

I'm running a CentOS 7 box. On this box I have two services which should both be exposed using port 443 for HTTPS traffic. Using a reverse proxy is no option, one service cannot be reconfigured to ...
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How to setup an Azure Firewall in a hub-spoke model to forward to the correct spoke subnets?

I have an Azure environment with different VNETs for each environment (dev, test, and so on). Each VNET has its own Azure Application Gateway with WAF enabled (due to the limitation on number of sites/...
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1answer
18 views

GCP Firewall - Deny by User Agent

Is it possible to block user agents in the Google Cloud Platform Firewall? I have a specific one I require to block. However as I offload SSL to the Load Balancer it is that which makes the request ...
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GeoIP blocking and fail2ban

Both involve adding firewall rules, is it worth implementing fail2ban as well as GeoIP blocking on the same system? Has anyone done this? Is fail2ban left with anything left to do or is it not worth ...
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Present multiple IP subnet on VPN/IPSec with Vyatta

I'm running Vyatta for setting up a VPN / IPSec. I need to receive 3 /32 subnets from the remote, and present 3 /32 subnets from my network. Do I simply add multiple rows in my config?: set tunnel ...
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Cyberoam Installation - Cannot Reach server Error

I have downloaded the Cyberoam tar file and have extracted it using tar command in the location /home/ec2-user which created a directory "CyberoamLinuxClient"inside which there were two files "...
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my gateway on linux mechine Restart Automaticaly [closed]

i am using Red hat on my local server and Created Gateway for internet providence.i have installed different Network Cards Kernel Interface table Iface MTU RX-OK RX-ERR RX-DRP RX-OVR ...
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Using Fritz!Box 3490 to forward external traffic to internal servers [migrated]

I have a Fritz!Box 3490 along with 5 usable external IPv4 addresses provided by our ISP. The Fritz!Box is to replace our existing DrayTek 2925. One of five IP addresses is an MX; so we use that IP to ...
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1answer
37 views

Possible to use Azure Application Gateway and Azure Firewall on AKS?

I have an AKS cluster running on Azure (managed Kubernetes). I'd like to put a WAF in front of it, using Azure Web Application Gateway. I think this is possible. But I also want a firewall in front ...
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Firewall rules for WebRTC and STUN

I'm trying to get a WebRTC service running, through a corporate firewall. The service works on the local network, but it appears that the firewall is stopping it from working globally. I'm using a ...
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2answers
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SSH from A through B to C, using private key on A

These is my scenario: Host C is not accessible from A. Host B is accessible from A. Host C is accessible from B. Both B and C have ~/.ssh/id_rsa.pub (from A) in authorized_keys B does not have the ...
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1answer
31 views

apache 443 connection refused error

so i'm running into a very funny, frustrating, and odd issue. I have a RackSpace webserver running a webiste. Lets calls it dummy.com. http://dummy.com is accessible on port 80 no problem. But ...
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1answer
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How to open a port in Linux for other users in same network?

I have an application running that is listening on port 7896. I can access that using localhost and port 7896 but other users in the same network can't access that using my IP address and port 7896. I ...
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iptables block dns port 53 access to specific LAN IP

I need help to block traffic dns/http/https using iptables for a specific IP (ex 192.168.1.36). But I have to allow only one site (ex: globo.com) The DD-WRT router is the network gateway (192.168.1.0/...
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2answers
52 views

Do I need routers in a LAN with 2-firewall DMZ solution? [closed]

I have a LAN that will host an EXTRANET site with 5 servers, and 2 exchange edge servers. The LAN will service an office in a 5 story building with about 100-200 users on each floor. Each floor will ...
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2answers
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pfSense: Allow VLAN Access to all but WAN

I have machines in a VLAN and I need to have them access all but not get out to the internet. I have tried this (and lots of others options) but nothing is working. I simply need to block internet ...
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2answers
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What is the downside of deleting an iptables rule as an attempt to check if it exists?

I want to add a rule using iptables, but only if it does not exist already. There's option -C which will allow us to check if a rule specification exists already. The option is described in this Q&...
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18 views

Correct firewall config for “Messages for Web” android sms website?

Having trouble with Google's hot new messages.android.com service. Most of the time it works great, but at my corporate office when my phone and laptop are on the corporate network it doesn't connect ...
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1answer
18 views

Can I filter based on a ICMPv6 subtype?

I'm trying to filter out specific ICMPv6 packets and I tried looking at all the possible types options by using the following command: ip6tables -p icmpv6 -h This yields the following types (note ...
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1answer
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iptables: Questions regarding the raw table

I can read all over the internet that the iptables raw table is only there to specify if connection tracking should not be applied. However, when a rules destination in the raw table is -j DROP for ...
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56 views

Why is my firewall rule not being applied?

I'm having difficulty getting the firewall on a Draytek Vigor 3220 to pass incoming connections to port 25. I've set a rule to pass TCP packets from WAN to LAN from any source IP address and port to ...
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19 views

IIS website only accessible over HTTPS (port 443)

I have my website running on IIS at hostname.com, with bindings for both http and https (I actually want to forward all http to https). From an external IP I can ping, telnet and visit the URL https:...
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1answer
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CentOS 7 - firewalld[8509]: ERROR: COMMAND_FAILED

[root@localhost ~]# systemctl status firewalld -l ● firewalld.service - firewalld - dynamic firewall daemon Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: ...
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1answer
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Changed AWS EC2 firewall rule and locked out of ssh

I have an AWS EC2 instance using SLES15. I manually edited /etc/sysconfig/SuSEfirewall2 to open some ports. I messed up the FW_SERVICES_EXT_TCP because I thought I am adding on top of what's already ...
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38 views

Unable to publish Django webserver on CentOS 7

I was working on my machine for Django project, and moved the project files to Linux server to publish the app. Currently I'm not interested in using gunicorn or nginx. I just would like to see if I ...
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3answers
61 views

Would a firewall occasionally disconnect an CentOS 7.3 NFS client?

When large read and write operations are conducted on a NFSv4 share on a CentOS 7.3 client, I notice that the NFS mounts often time out. Does a fresh, out-of-the-box installation of CentOS 7.3 ...
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1answer
20 views

Cant open ports in VPS Win Server 2016(AWS)

i'm trying to open ports 7171, 7172, 80 in Windows Server 2016 at AWS. I already opened them in Firewall, then i tried to turn firewall off but i still unable to acess my xampp website through port ...
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Cisco ASA 5515 - huge amount of long running idle connections

I've got a Cisco ASA 5515 and it's come to my attention that the connections usage is quite high. Here's the result of running show resource usage summary Resource Current Peak ...
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1answer
71 views

Unable to block port 25 on server

When I scan my server using nmap $ sudo nmap -sS IP.ADDR.OF.SRVR, I see a line with 25/tcp open smtp. This is despite the fact that I'm not running postfix, exim or any other kind of mail server ...
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1answer
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How to protect VPS by UFW firewall properly?

I set up a fresh VPS on DO and now I'm trying to protect my server using UFW firewall. But, I'm confused just a little bit. So, my goal is to allow the only SSH, HTTP/HTTPS related ports. The rest ...
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26 views

How to list iptables/ebtables rules corresponding to a libvirt network filter?

libvirt network filter webpages says, The network filtering subsystem is currently only available on Linux hosts and only works for QEMU and KVM type of virtual machines. On Linux it builds ...
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tcptraceroute: Hop does not reply

AFAIK tcptraceroute is the best tool to check if a firewall is blocking the tcp connection to a service. (If you know a better tool, please let leave a comment) Some hops do not reply. See * * * ...
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1answer
73 views

rpcapd behind a firewall

I have a remote server with rpcapd installed that follows strict security policy rules. Any client can access to the server only via firewall that follows same security policy (please, don't blame me, ...
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How can I allow packet forwarding via Windows Firewall? [duplicate]

In the Linux I can use iptables for enable forwarding: ~ # iptables -I FORWARD -j ACCEPT But how can I realize the same function in Windows?
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2answers
68 views

VPN Connection to Windows Network behind Firewall

We have a Windows network with a single Windows Server 2012 server which works domain server as well as a file server, which is protected by pfSense firewall. We want to allow a specific user (with ...
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35 views

Windows Firewall: 2 Sets of remote inbound rules deployed by 2 different GPO's

I'm looking to create 1 gpo with f/w inbound access rules for just our management server ip's at a high level in the group policy tree. As you drill down under our sites I'm looking to create a 2nd ...
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44 views

block specific string with iptables rules

I want to block a strings with iptables rule, but i want to know the best way to do it. For example, i have this 4 rules: /sbin/iptables -t mangle -A PREROUTING -p all -m string --hex-string "|...
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1answer
32 views

Firewall Recommendation GCP

We have hosted our platform on Google Cloud. Its a startup and its pretty lean setup with 1 X Nginx | acting as a web server | Public facing subnet 1 x Database server | internal subnet enter image ...
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1answer
44 views

Configuring MikroTik RB 750 GL to have switch as WAN and Ether1 as NAT to LAN

My ISP allows me to have multiple static IP addresses. I want to use a RouterBoard 750GL to attach multiple publicly addressable servers to the internet using Ether[2-5] in switch mode, and use Ether1 ...
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0answers
38 views

windows server 2016 hacked for the third time [duplicate]

hello everyone I'm using a windows server 2016 as web server that runs a WebLogic application on a specific port (7001) and I have almost done every thing I know or I read about on the internet to ...
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39 views

How to find a windows firewall rule that's allowing access?

I'm trying to disallow remote access of Tomcat's port 8080 and only allow localhost access, as far as I know (I'm not great at Windows administration) Window's Firewall is default deny, so what I ...
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0answers
25 views

How solved problems firewall by ejabberd

I can install ejabberd 18.06 on windows server 2008 by but no login from other external client o other connections. SEND.CLIENT> <body rid='1986147588' xmlns='http://jabber.org/...
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1answer
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Changed SSH port from 22 to 1234, but port 22 still shows when I run nmap?

I used this article to change my ssh port on a centos 7 box: https://www.liberiangeek.net/2014/11/change-openssh-port-centos-7/ (I skipped the selinux stuff as I don't have that installed): But ...
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1answer
72 views

Windows Firewall - difference between disable and “block”

In "Windows Firewall with advanced security", what is the difference between disabling a rule and setting it to "block traffic"? Besides knowing the difference, in my case I want to diminish the ...
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1answer
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Windows Firewall notifies network uses after updating exe

We have a software made in NWjs with auto-update. Recently we publish an update and some clients report firewall notification after download this update. Now a need to know if is there a way to ...
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0answers
68 views

Firewall Kubernetes using Calico

I've created a Kubernetes cluster with calico as network plugin. It's working fine. Now I try to setup the firewall. What rules do I need for calico? I can only find rules for flannel. At the moment ...
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0answers
34 views

Routing between OpenVPN subnets in tunnel modes

Hope someone can help me and understand what is wrong in my setup. I have installed OpenWrt Chaos Calmer 15.05 on m TP Link router. The router have the WAN connected and a WiFi and wired subnet on ...
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1answer
45 views

FirewallD not loading rule after reboot

I have FirewallD on Ubuntu Server 18.04. Got allowed services ssh http ipsec. But on reboot, firewall always allow ssh, ipsec but block http. To solve this, I have to run firewall-cmd --reload every ...