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

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Remote WOL over CISCO/FW not Forwarding

I'm trying to accomplish a Wake-on-LAN by triggering the two servers' public IP addresses. Internally, the WOL works like a charm (by either the internal or external IP), externally however, it does ...
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1answer
65 views

why my nat iptables rules dont work with marked packets?

System: debian squeeze, Linux server 2.6.32-5-amd64 #1 SMP Tue May 13 16:34:35 UTC 2014 x86_64 GNU/Linux, iptables v1.4.8 lsmod | grep iptable iptable_security 2176 0 iptable_mangle ...
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1answer
62 views

How to route VPN traffic through a separate internet connection with a SonicWALL firewall?

We have a depot quite some distance from the exchange, the expensive internet connection is only getting 2/1Mb. This causes constant drops as soon as someone downloads anything. We have now got a 4G ...
0
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1answer
46 views

rDNS and forward DNS for mail server behind firewall, different IPs

All, Here is my setup : Firewall(x.x.x.114) <--> mail.mailserver.com (FQDN) (x.x.x.118) When sending mail, header has following IP ...."Receivedfrom mail.mailserver.com ([x.x.x.114])", my ...
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1answer
44 views

Cannot find error in iptables firewall configuration

I'm struggling with a firewall problem on my Centos server. I have the following configuration which when I use it with a service iptables restart and I try to ssh to the server with putty, I cannot ...
0
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1answer
26 views

Adding VPN/Firewall to my network

Right my setup is as follows TP-LINK AC1750 Wireless router WAN (Comcast) connects here 1 port connects to TP-LINK 16 port managed switch 16 port switch has static IP, 192.168.0.99 (I've reserved ...
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1answer
60 views

Configuring iptables for Haproxy

Ubuntu machine running haproxy with 2 network cards, 1 connected to WAN (called wan0) and another connected to LAN (called lan0). All chains set to DROP traffic. # Masquerade traffic from LAN to WAN ...
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0answers
87 views

ZyWall USG-100 Firewall block access to internal subnet beyond another router

I'm experiencing a strange problem with a ZyWall USG 100 Firewall, that I can't solve with leaving the firewall enabled on the ZyWall. I have the main network subnet that is 192.40.192.0/24(LAN1 on ...
2
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1answer
108 views

Block smtp service to a IP centos 7 Firewall

I would like to know how to block an IP to use smtp service on a server with centos 7 firewall . I try to use something like this : firewall-cmd --permanent --zone="public" --add-rich-rule='rule ...
0
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1answer
73 views

How will the LAN to LAN firewall rule affect the traffic in the rest of the network

I have a following network setup (of course a bit modified from the real situation) I would like to setup a LAN to LAN rule on the ZyWALL firewall so that only certain ports/ip adresses are allowed ...
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36 views

rsyslog not discarding despite rule to the contrary

I am running rsyslogd on a new CentOS 6.6 box. I have put in a custom rule to log my firewall messages (via firehol) to a separate file, as per instructions here: ...
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48 views

How to block ip/ports using iptables with specific date and time?

Normally to block in command-line I used iptables. iptables -I INTPUT -s xxx.xxx.xxx.xxx -m time --utc --datestart 2013-09-09T15:00 --datestop 2013-09-09T15:30 -j DROP But the problem is, this ...
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0answers
37 views

How to forward traffic from ipsec host to local network?

Could anybody explain how to implement forward traffic from host in IPsec to local network. On my server I have 3 network cards: red0 - extern orange0 - dmz green0 - local IPsec builds through ...
1
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1answer
71 views

Can't get iptables working in VPS - state and conntrack not possible

I've been browsing and reading documentations all night and I can't figure out any solution... I'm trying to get iptables working on my VPS (Debian 7). But I can't get established connections ...
2
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2answers
71 views

Can't SSH, but can TeamViewer [closed]

I would like to SSH into a computer behind a firewall that blocks SSH connections (incoming and outgoing). Amusingly, I can still access the computer using the remote-desktop software TeamViewer. I ...
1
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0answers
27 views

UFW Firewall on Ubuntu

I have installed UFW on Ubuntu 14.04. I used following commands to enable a port: sudo ufw allow 9384/tcp When I used the status command (sudo ufw status) it shows me that port is open for both IP4 ...
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3answers
40 views

Can the firewall prevent the DHCP to give an address, how to fix this?

I am not getting an IP in the subnet 10.0.0.0/24 where the DHCP is working and should serve an IP, I am getting instead only an IP in the subnet 169.254.0.0/16(link local address) that is probably ...
0
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0answers
12 views

FreeBSD pf does not allow inbound smtp [duplicate]

I'm trying to figure out why the following simple pf config allows inbound SSH but not smtp (tcp 25). I'm running FreeBSD 10.1-RELEASE-p9, and the SMTP server is postfix 2.11.4. # ...
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2answers
83 views

Port forwarding ssh with iptables

Moved from stackoverflow... My new Internet firewall, based on Linux iptables, is working in most regards very well, but the port forwarding does not work: $ ssh -p 7022 [ppp0-ip-address] ssh: ...
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0answers
117 views

Make NGINX Block All Requests To Direct Server IP - Stop XML-RPC Attacks

Essentially, my website is being attacked by a layer 7 XML-RPC attack and is currently offline and has been offline so I am in need of desperate help. Any assistance would be greatly appreciated :)! ...
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1answer
65 views

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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0answers
38 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 ...
0
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1answer
174 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 ...
1
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1answer
59 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 ...
1
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1answer
78 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 ...
2
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1answer
35 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. ...
0
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0answers
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 ...
2
votes
1answer
61 views

How to test iptables settings by port scanning? [closed]

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?
2
votes
1answer
151 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. ...
1
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1answer
133 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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75 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 ...
0
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1answer
43 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. ...
0
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1answer
20 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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votes
3answers
104 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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69 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 ...
53
votes
5answers
7k 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 ...
2
votes
1answer
55 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 ...
2
votes
2answers
990 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
430 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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votes
3answers
166 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 ...
3
votes
1answer
36 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
33 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 ...
0
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1answer
191 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 ...
3
votes
3answers
177 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 ...
0
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1answer
59 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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0answers
48 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 ...
3
votes
1answer
177 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
56 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 ...
2
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0answers
47 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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0answers
27 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 ...