A firewall is a program that controls the incoming and outgoing network traffic on a system. Use this tag for all questions related to firewall configuration and operation.

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Disable networking only inside of a single terminal

I want to run a command in the terminal to disable networking, just in that terminal. How can that be accomplished? I'm running OSX. Note: I only want to disable the networking in that terminal. ...
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0answers
18 views

NFS Port Blocking Firewall Issue

I am a little stumped on this one and maybe I have been staring at this for too long...but I cannot get my Mac (10.10.3) machine to connect to my Oracle Linux 7 (CentOS/RH 7) server with its firewall ...
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19 views

How to create a rule on IPCop firewall for bittorrent trafic to work properly?

I've been trying to use my favourite torrent client (µTorrent) after setting up my IPCop (last update 2.1.9) and it warned me that my router/firewall was blocking the traffic and that I had to open a ...
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1answer
32 views

Unable to access another server over local network on Digital Ocean

I have two servers. Let's call them A and B. Both are running ubuntu server 14.04. B runs percona server. Now I do not have any firewall set-up on either servers still I am unable to connect to server ...
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0answers
16 views

Forcing google/youtube safesearch on Ipfire

I use IPFIRE firewall os and even though it has a force safe search feature it doesn't seem to work. Would there be any other way to force this feature as I cannot seem to. Create a new cname in ...
2
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1answer
42 views

Close the neccessary Ports [duplicate]

I am using Linux Mint and I am newbie. Someone is trying to access my computer via my MAC Address and open port. I have some questions: I know that there are different type of port like TCP and UDP. ...
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0answers
49 views

Can't access Apache test page in desktop browser? [on hold]

I've installed Apache on CentOS 7 (virtual machine) and haven't touched any of the current settings. I've started Apache and made sure I was connected to a network. Using the elinks browser, I'm able ...
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0answers
65 views

How can I redirect internet traffic from local to proxy server with ip tables (DEBIAN 6)

So i made topology as shown in figure. Router have 3 interfaces like this: eth0 to internet side (with ip 192.168.1.10/24 gateway 192.168.1.254/24). eth1 to server-PC side (with ip ...
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2answers
39 views

Connection Timeout for ssh connection depending to the ip location?

I have a machine where I can connect it using ssh from different networks. But when I have moved to other country I have not be able to connect it. What may be the cause? I am able to ping the server ...
0
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1answer
26 views

mount times out with iptables --policy OUTPUT DROP

I previously ACCEPTed all output traffic by default. Recently changed the policy to DENY output by default, only opening ports needed for server/application functionality. When I tried to mount a ...
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0answers
56 views

CentOS as home network router: IPTables Port Forwarding failure

I have currently set up a home server with a CentOS 6.6 installation on it. The server has two NIC interfaces which I'm using it as my router and DHCP server. Here's a diagram showing the network ...
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0answers
21 views

CSF not blocking port when removed from csf.conf

I have removed VNC port 5901 from the csf.conf configuration file and executed a csf -f a csf -x and a csf -e to flush and restart CSF. There is a vncserver running on port 5901 and when doing an ...
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3answers
61 views

how to automate creating firewall rules?

There is a complex live system - few vlans. In each of them there are linux servers, and on every server there are services. Services connect together - for example service http on host A connect to ...
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0answers
50 views

Opening a TCP port in Linux

I am trying to establish a TCP socket between my linux server and my client running on my laptop. The TCP server code I am running is, from socket import * HOST = '' PORT = 1999 ...
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0answers
20 views

Shorewall configuration : providers and LAN

Hi all and thanks in advance for the answers. Currently, I have different providers configured in shorewall. I'll will probably have to change one of them. The problem is I won't have any Public IP ...
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2answers
37 views

Impossible to browse web after configuring iptables

I'm trying to configure iptables on my ubuntu computer. These are my rules: Chain INPUT (policy DROP) target prot opt source destination ACCEPT tcp -- anywhere ...
1
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1answer
38 views

Email evading my spam filter

I'm having trouble with email evading my Barracuda Spam firewall. I believe the spammers are using my A Record to bypass my MX Record which is what directs email to my Barracuda for processing. How ...
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0answers
19 views

how do I disable the firewall through YaST?

The fine manual states: The Start-Up section defines how your firewall will start. You can either have the firewall start automatically when booting (recommended), or you can set the firewall ...
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0answers
61 views

can't connect to remote host with MySQL…firewall problem?

I've granted privileges to thufir for remote access through the shell (correct?), but cannot seem to actually connect. The router firewall has SPI to off. I've disable the IPv6 firewall on the ...
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0answers
22 views

why do we have same chains in different tables of “iptables firewall” in linux?

why do we have same chains in different tables of "iptables firewall"? Like for example: we have "output" chain in filter table, nat table & mangle table.
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28 views

how to set a route and firewall for a static ip

These directions on setting the static ip address for vicidial seem at once very specific and overly broad: Type 'yast lan' and press ENTER Optionally, you can type 'yast' and navigate to the ...
0
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0answers
36 views

Unable to ping/SSH web-facing server

I just installed Ubuntu 14.04 LTS onto a box that's set up with one local NIC and one web-facing NIC. The web-facing NIC is configured with a static IP per my ISP. Because networking and security ...
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0answers
34 views

How do you tweak iptables limit rules on openSUSE Tumbleweed?

I have a fresh install of openSUSE Tumbleweed, it is logging a lot firewall related stuff due to my apple devices multicasting to enable airplay. Lines look like: Mar 14 12:45:13 server kernel: ...
1
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1answer
31 views

How iptables tables and chains are traversed

I know linux has 3 built-in tables and each of them has its own chains as follow: FILTER: PREROUTING, FORWARD, POSTROUTING NAT: PREROUTING, INPUT, OUTPUT, POSTROUTING MANGLE: PREROUTING, INPUT, ...
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0answers
27 views

TCP connections in SYN_SENT not visible with lsof

I have lots of connections in SYN_SENT: $ conntrack -L | grep -c 'SYN_SENT' conntrack v1.2.1 (conntrack-tools): 28100 flow entries have been shown. 14017 But I can't see which process(es) are ...
3
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2answers
52 views

How to disable network access for a user?

Trying to disable the network access for the user: [root@notebook ~]# iptables -I OUTPUT -m owner --uid-owner tempuser -j DROP [root@notebook ~]# ip6tables -I OUTPUT -m owner --uid-owner tempuser -j ...
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23 views

Forwarding packets through a host

I've setup a Site-to-Site network using this How To This How To fits exactly what I need. But I've a problem. From site wich hosting the OpenVPN AS server (site 2, right in the howto) I can't ping a ...
2
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0answers
45 views

Why is traffic matching the public zone instead of the desired zone?

Trying to self-train on firewalld I set up apache and configured the zones as follows: [root@localhost ~]# firewall-cmd --get-active-zones work sources: 192.168.122.1 public interfaces: ens3 ...
4
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3answers
55 views

OpenBSD's pf: disable network access for a given user, except for ssh.

If we are using the default firewall for OpenBSD, how can we modify it to disable all the network access for a normal user except for one thing: we want to ssh to the user from random hosts! So ...
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0answers
24 views

ufw firewall - how to only “allow” when I am going through a proxy

I am using a proxy to navigate on internet, and I am trying to setup a firewall that will only let me connect to internet via this proxy: if I forgot to turn on the proxy, that I should not be able ...
0
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1answer
79 views

IPTables Firewall/Router/Gateway needing to block outbound traffic from users

I have multiple ethX interfaces. eth0 is connected to the internet. eth1 is connected to a trusted network. eth2 is connected to a network I need to impose usage rules. What I'd like to do is ...
0
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1answer
106 views

How to open server port on RHEL 6.6?

I am trying to open a port (tcp 27017) for access to mongodb on a newly created RHEL 6.6 instance at Amazon AWS. Following mongo docs, I did: sudo semanage port -a -t mongod_port_t -p tcp 27017 I ...
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0answers
78 views

OpenWRT on embedded device as firewall

I have the following setup in my network: My internet comes in through an ATT Uverse modem/router. The router is in bridge mode because that ATT Uverse modem/router connects to a second higher ...
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0answers
55 views

PPTP Through IPTables

If this has already been answered, I apologize, I could not find an answer to this during my searching. I am new at Linux/Unix and I have recently implemented a Raspberry Pi firewall/gateway on my ...
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1answer
187 views

firewalld settings for OpenVPN with https, ssh, and smtp

I am configuring a remote CentOS 7 webapp server to wrap https and ssh inside OpenVPN, while keeping smtp running outside of OpenVPN. I notice that, when I establish an OpenVPN connection from a ...
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1answer
181 views

multiple user-types/access-rules for OpenVPN on CentOS 7 and firewalld

How can I define separate roles for users and administrator in OpenVPN running on CentOS 7 server? Specifically, the users must only be allowed to https, while the administrator must be allowed to ...
0
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1answer
69 views

How can I set up the ULOG target with iptables and MySQL

I'm running CentOS 6.6 32bit as a firewall box using iptables. I want to be able to use the ULOG target to store dropped packets in a MySQL database for statistical analysis. After much Googling I ...
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0answers
41 views

Redirect all ARP traffic from eth0 to eth1

I would like to redirect ARP traffic, but I'm struggling with arptables and ebtables. I have 2 interfaces: eth0 10.10.10.25 eth1 10.10.10.20 Both in 10.10.10.0/24 I want to redirect the ARP ...
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2answers
32 views

FTP and WWW services don't acknowledge connections

I have Lubuntu 14.04 LTS with vsftpd and the lamp stack (apache2, etc.) installed. Everything works fine on the LAN. Externally, the services don't acknowledge connection attempts. I can see packets ...
0
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1answer
81 views

Stateful user-space firewall for Linux

Is there any stateful user-space firewall for Linux? I'm looking for a firewall that doesn't rely on anything in Linux kernel (like iptables/netfilter) and works with raw packets.
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1answer
68 views

Open UDP Ports; Can I Close Them?

I'm trying to secure my internet browsing. I just reinstalled Xubuntu 14.04 and GUFW firewall. I have 8 UDP ports open. I don't understand why. The software I currently have open are Firefox, GUFW, ...
0
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1answer
18 views

What port uses my backportpackage or bzr?

I am working in a company what uses Ubuntu Precise on the desktops behind a proxy. The Proxy is available in /etc/environment and set as: http_proxy, https_proxy, ftp_proxy, no proxy and their ...
2
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1answer
149 views

How to use both syn proxy and connlimit rules with iptables?

I want to write both syn proxy and connlimit rules. I want to send packets to syn proxy first because of performance issue. Here is rule sample. I use bridge interfaces but I dont think it is ...
0
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1answer
15 views

kernel security and IDS Firewall + AV together or not?

I try to hardening my server. For doing so, I got a general question: Should I install kernel security patches like selinux and an Anti-Virus with Intrusion Detection Firewall? Does it make sense to ...
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0answers
106 views

How to setup reverse FTP in RHEL?

Researched: http://www.thecave.info/export-proxy-username-password-linux/ http://stackoverflow.com/questions/5334110/text-based-ftp-client-settings-behind-a-proxy ...
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1answer
157 views

Which port to open for Google HangOut Video Conference

We need to open the necessary ports for Google Hangout VIDEO Conferencing in our firewall. Unfortunately my netmon trace shows Port 51355 and 51336 to be active; which is not at all what the Google ...
3
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1answer
303 views

Changed SSH port without allowing it through firewall, locked out now - what to do?

I have a VPS where I changed the SSH port from the default 22. Unfortunately I forgot to allow the new port through the firewall. I don't have physical access to the server, and my host does not seem ...
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0answers
62 views

firewall-cmd forward rules for interface with multiple ips

I'm looking for a way with firewall-cmd or another command to do the following. An incoming public interface has multiple ip addresses bound to it. How can I forward ports only for one of the ip ...
3
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0answers
97 views

iptables: using “conntrack” and “recent” modules to block unsolicited packets

When I only allow RELATED and ESTABLISHED packets, and DROP everything else, my firewall rules work perfectly and I have no problems: ### VARIANT A -A INPUT -i wlan0 -m conntrack --ctstate ...
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3answers
288 views

what is dhcpv6-client service in firewalld, and can i safely remove it?

In a CentOS 7 server, I type in firewall-cmd --list-all, and it gives me the following: public (default, active) interfaces: enp3s0 sources: services: dhcpv6-client https ssh ports: ...