iptables is the userspace command line program used to configure the Linux 2.4.x and 2.6.x IPv4 packet filtering ruleset. It is targeted towards system administrators. Please, when asking a question about iptables, add the output from the following command: iptables -L -v -n

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1answer
33 views

Iptables: some ports are closed despite being open by my iptables; can it be something else?

Beginner question. I set up the following iptables rules: #!/bin/sh # Réinitialise les règles sudo iptables -t filter -F sudo iptables -t filter -X # Bloque tout le trafic sudo iptables -t ...
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votes
2answers
56 views

Differences between iptables and ip6tables processing of packets

I've reviewed a variety of netfilter, iptables, and ip6tables resources. I've searched Google, including StackExchange websites for information, and, I can't find easy or clear links to information ...
15
votes
6answers
2k views

Will blocking all connections outside of the US, aside from port 80 cause a high server load?

Like most servers (I assume), we have people trying to brute force our services 24/7. I have cpHulk blacklist their IP's, but it seems like it'd be better if they didn't get that far in the first ...
0
votes
1answer
44 views

transparent proxy (SSL error)

Right now we are having transparent proxy in our network environment. we have been set proxy settings to browsers in all systems. While accessing the https sites in browsers no issue but few of ...
0
votes
1answer
29 views

General approach for isolating a WLAN with iptables? [closed]

I'm trying to use a 2-port plus WiFi adapter NAS as a home router, and I'd like to know roughly how big an undertaking the following would be using iptables: forward masqueraded client traffic from ...
0
votes
1answer
218 views

Linux: Bridge two NICs and route traffic through VPN tunnel except specific destinations and ports

I have a Linux PC (Debian Wheezy) with two Ethernet adapters. Adapter eth0 is connected to the Internet (modem/router/DHCP/firewall thingy) and eth1 is connected to an WiFi access point. All other ...
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votes
0answers
33 views

PCI says port 36141:TCP is blocked. But 36141:TCP open on iptables

PCI compliant scan fails due to port 36141:TCP is being blocked on website. I verified I cannot connection via 36141 on same server to itself: # nc -zv 127.0.0.1 36141 nc: connect to 127.0.0.1 port ...
2
votes
1answer
49 views

Squid problems with iptables

I've installed and configured Squid on Fedora Server 21 with full updates. My proxy's IP is 145.130.33.133 with port 3128. First I modified my squid.conf with my rules and everything. On my laptop ...
0
votes
1answer
62 views

iptables - openvpn can't access port 80

I have a server set up with OpenVPN. While connected to the VPN, all external websites work great, but when I try access a site that is hosted on the same server, it fails to connect. I can ssh into ...
3
votes
3answers
163 views

Advanced dynamic routing with external program

I need to build a system in which i am able to route packets based on a number of parameters, such as port/protocol etc, which are somehow "normal", but also on other aspects, such as queue length, ...
0
votes
1answer
50 views

Port redirection with iptables to localhost / blocking the destination port

I like to forward all traffic coming to 80 to be redirected to 8000. I used iptables -tnat -A PREROUTING -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 8000 But then port 8000 is still open to ...
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vote
1answer
38 views

Why can't I connect to my remote MySQL Server?

I have a asterisk server that is set up in on a VPS provider. I need one of my local applications to connect to the database to pull reports, but I am having dificulty getting a read only connection ...
1
vote
1answer
152 views

Configuring IPtables to mirror traffic in CentOS

I'm trying to set up iptables to mirror traffic coming into eth2 and send to 10.1.4.4. I have been reading a lot of documentation on this but am having some issues. Here is the command I am trying ...
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votes
1answer
25 views

Redirect port without opening it

I have the following iptables configuration iptables -P INPUT DROP iptables -A INPUT -i eth0 -p TCP --dport 443 -j ACCEPT iptables -A INPUT -i eth0 -p TCP --dport 10001 -j ACCEPT iptables -A ...
-1
votes
1answer
110 views

UDP reverse proxy on Linux [duplicate]

I have a dedicated server which hosts game servers, and is vulnerable to DDoS attacks. I want to get a DDoS-protected VPS to act as a reverse proxy for UDP. The dedicated server's IP address is ...
1
vote
1answer
71 views

iptables connlimit: exclude multiple IP addresses

I have currently this IPTABLES command: iptables -A INPUT -s ! 192.168.0.2 -p tcp --syn -m connlimit [...] -j DROP As far as I know, such rule limit some number of connections following various ...
0
votes
1answer
38 views

Iptables overridden after reboot in Ubuntu server

On my Ubuntu server (installed KVM and Kimchi), I noticed that the iptables are changed after a reboot. Unfortunately I did not find out which script is responsible for these changes. I tried to ...
0
votes
1answer
23 views

Inbound IPTables rules based on queried domain

I have an odd situation and I'm not entirely sure if it is even possible in IPTables. If it isn't, that's fine and I can do without. If it is, fantastic, I'd love to see how to implement it. So, my ...
1
vote
1answer
95 views

Port suddenly closed. How to re-open?

I've written a software module in PHP that manages the saving of data in different data stores (MySQL, ElasticSearch and Redis). To test the module, I've created several test plans in Apache JMeter, ...
0
votes
0answers
52 views

Why iptables block my port 80 traffic?

I've setup a configuration on iptables to allow only the traffic I need. I opened the port 80... but with iptables enabled, I cannot reach my site. This is the configuration... Where I've made some ...
0
votes
3answers
67 views

How to route all local trafic to Squid?

I have a working squid caching server which is accessile through 127.0.0.1:3128. I'm trying to route all my trafic(and if possible all my virtual machines) to 127.0.0.1:3128. I'm using vagrant and ...
0
votes
1answer
18 views

Linux Traffic Shaping: ceil rate never reached

My application run on port 8080. I have this iptables command: iptables -A OUTPUT -t mangle -p tcp --sport 8080 -j MARK --set-mark 10 I have also theses TC rules: tc qdisc add dev eth0 root handle ...
0
votes
1answer
38 views

IPTables Rules Being Loaded From Somewhere

I'm having troubles connecting (meaning I can't connect to any IP or port) to my server and it appears that the problem was to do with CSF. I uninstalled CSF (by running /etc/csf/uninstall.sh) and ...
4
votes
1answer
80 views

Forwarding a port on the loopback interface to a remote IP/port

I have two Docker containers that I'm trying to network together in a specific way. Container A is running a Redis server on port 6379. Container B is running an interactive shell and needs to access ...
0
votes
1answer
37 views

Connecting to web server through eth1

So I am having issues with connecting to my web server via eth1. ifconfig eth0 Link encap:Ethernet HWaddr 00:50:c2:27:bf:6e inet addr:10.8.105.8 Bcast:0.0.0.0 Mask:255.255.0.0 UP ...
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votes
0answers
68 views

Does firewalld handle the common attack rules of iptables by default?

I'm in the process of migrating servers to CentOS 7 from 6.5 and the most major change appears to be the shift from iptables to firewalld. My prior experience with iptables tells me that there are a ...
1
vote
0answers
53 views

OpenVZ : live migration fails

I can't launch live migration of OpenVZ container between two proxmox nodes... Feb 05 03:30:27 starting migration of CT 102 to node 'madrid' (xx.xx.xx.xx) Feb 05 03:30:27 container is running - using ...
1
vote
0answers
26 views

Clone and then route SNMP traps to new destination

We have 2 SNMP trap servers 10.0.0.1 and 10.0.0.2 which are the SNMP trap servers for close to 500 devices that we monitor.In all these 500 devices,10.0.0.1 and 10.0.0.2 are configured as the trap ...
0
votes
2answers
64 views

Port not accessible on Linux server

I started local server using php on my server php -S 0.0.0.0 8283 -t testServer/ using curl localhost:8283 I am able to get the result of the index.php file but when I access it using my server ...
0
votes
1answer
33 views

How do I use iptables to modify SRC based on DST PORT and also modify DST PORT

I have an interesting problem. I have a client machine IP 10.10.10.55 that needs to connect to a server machine IP 10.10.10.5 They are both windows machines, and they both go through a gateway linux ...
0
votes
1answer
109 views

Linux: limit specific port rate by combining tc with iptables does not work as expected

The script blow tries to limit the incoming rate of the port 2000, when using iptables to mark the INPUT packets does not work, but OUTPUT works fine. I use nc -kl 2000 on machine 10.0.1.54 and iperf ...
0
votes
1answer
55 views

Cannot access server on port different than 80

I'm hosting a server on Rackspace. Generally I have some domain name that i redirect to my ip and use nginx for the internal routing. This is my default configuration: server { listen MY_IP:80; ...
0
votes
0answers
56 views

Route sql server traffic through firewall

We currently host our web application on multiple servers using Rackspace Auto Scale. This causes our outbound IP addresses to regularly change. At the same time we need to connect to an external sql ...
0
votes
0answers
50 views

Routing VPN traffic between two networks

I have recently set up a two-network bridge using OpenVPN (Connect two networks with OpenVPN) The following things work: -Pinging any Network 2 computers from Network 1 Gateway (10.0.1.9) -Pinging ...
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votes
1answer
81 views

What is the easiest way to block access from all countries except for one? [closed]

I have a Ubuntu 14.04 server which runs a game server and it's under heavy DDos attack right now. It's not a English-speaking community, so I don't need access from any other countries but mine. All ...
2
votes
2answers
143 views

iptables drops packets after POSTROUTING

I have a malware analysis environment that will intercept traffic to arbitrary domains and Internet services using InetSim. I have a sandbox that has its DNS server set to the InetSim instance, and ...
1
vote
2answers
105 views

Need to restart iptables after server shutdown

I have a server acting as host (KVM), proxy and firewall. In order to access the services provided by the virtual machines in this host, iptables must work in order to redirect the packets properly to ...
0
votes
2answers
83 views

should iptables be this long? many chains?

Ok, this is a brand new install of CentOs 7 (minimal). This is the iptables -L Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ...
1
vote
2answers
40 views

Trying to use source routing on two different interfaces

I have defined the following rules: -A POSTROUTING -j SNAT --to-source [publicip] -A POSTROUTING -j SNAT -d 192.168.0.0/24 --to-source 192.168.0.6 Basically, I want only the private network to go ...
0
votes
2answers
164 views

Connect two networks with OpenVPN

I am trying to connect two networks together via OpenVPN. Gateways can ping each other, however they cannot access other computers on the network they're joining. Logs don't show any errors, and the ...
1
vote
2answers
188 views

fail2ban error on setting iptables on Synology NAS

I setup fail2ban 0.9.1 on my Synology NAS to handle failed SSH attempts. When I startup the jail I get the following errors in fail2ban.log: 2015-02-01 17:22:52,394 fail2ban.jail [30576]: ...
1
vote
0answers
38 views

Redirect incoming WAN connection to other WAN host with iptables

I have router with Linux. I want to redirect incoming WAN connections with specified port to some other WAN host:port. I've tryed do this standard way: iptables -t nat -A PREROUTING -p tcp --dport ...
0
votes
0answers
54 views

VPN server with mitmproxy

I have a mitmproxy script I want to run on all incoming VPN HTTP/HTTPS traffic, however, I am not sure how to achieve this. Is there a linux VPN daemon that allows me to redirect traffic to a ...
2
votes
1answer
164 views

Multicraft: Port Forwarding through a GRE Tunnel

For the past week I've been attempting to protect a server from DOS attacks by utilizing a GRE tunnel from a VPS to a dedicated machine without much success. Visual: User --> VPS --> Dedicated ...
0
votes
1answer
61 views

CSF Update resets IPTables rules

This is with CentOS 6. On one of my servers, periodically all IPTables rules are simply dropped and all connections start being blocked. It happens fairly randomly once every few days. I have a script ...
0
votes
0answers
39 views

How to access connected devices to a remote router using OpenVPN?

After much confusion I have finally managed to connect Windows 7 box to a remote 3G router using OpenVpn. The Windows 7 box is set to run as a OpenVPN server(10.8.0.1) and the 3G router is set as a ...
0
votes
0answers
68 views

Chaining two containers with docker

I have two containers that I have chained them together, so traffic that comes to container 2, first passes by container 1. I set container 2 --net=none. Host --- Container 1 --- Container 2 this is ...
0
votes
1answer
69 views

How to pass all traffic through virtual ip on linux

I have an Ethernet card on CentOS server. It has been configured: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000 link/ether 40:f2:e9:9b:b7:bb brd ...
0
votes
1answer
40 views

Simulation of TX/RX Drop

I'm trying to get the "TX/RX Drop" values to increase. I've tried dropping packets using both iperf and iptables but the statistics aren't increasing even when packets are being dropped. Is there a ...
0
votes
1answer
85 views

Cannot connect on port 80 to Azure Ubuntu machine

I have recently set up a Linux Ubuntu VM on Azure. I can SSH into the machine just fine, but HTTP requests are answered with "Connection refused". I have: Set up an Endpoint for port 80 in the ...