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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18 views

Cannot create a valid BPF program: bpf: check failed: parse error

I am trying to use xt_bpf iptables module to match for UDP DNS packets that have Recursion Desired bit set. I am slowly building my BPF program in assembly and compiling it through bpfc from ...
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1answer
30 views

Ubuntu Iptables FTP passive mode

I have a problem when trying to define iptables rules in my ubuntu server. I reject all connections and allow some like FTP. The problem is that in passive mode I can connect but I cannot list ...
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0answers
22 views

Limiting bandwidth to a specific IP

My question is very similar to http://serverfault.com/a/191605/253872 however I wish not to limit someone on my network, but traffic from my server to a specific IP. In reference to the script in the ...
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2answers
41 views

I cant open a port iptables - The command runs, but port keeps closed [closed]

I want to make a simple redirect of my notebook port to a VM port (in my notebook also).. iptables -I INPUT -p tcp --dport 2424 -j ACCEPT iptables -t nat -A PREROUTING -p tcp --dport 2424 -j DNAT ...
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1answer
38 views

Original IP lost with IPTables NAT to another server

I'm trying to forward all HTTP traffic from one EC2 linux server (external IP 11.11.11.11) to another one (external IP 22.22.22.22), these rules set: sudo iptables -t nat -A PREROUTING -p tcp --dport ...
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1answer
26 views

Restrict only 1 file to use sendmail

I want to restrict access to sendmail process, to only 1 php file /var/www/mysite/contact.php How can I do this? Maybe there is a trick with Iptables or sendmail configuration? I want to secure ...
1
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1answer
37 views

Can't access to a port (which is running Spring boot jar) via it's public ip

I have deployed my spring boot app jar to centos server with this command: nohup java -jar black-0.0.1-SNAPSHOT.jar > log_black.out & In my application.properties I set the server port ...
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2answers
67 views

iptables: trying to block port 53 but not working

I'm messing around with IP tables and I'm trying to do the following: I have several hosts on the same network: 192.168.1.0/24. The DNS server is 192.168.1.1. I'm trying to prevent all the hosts ...
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0answers
57 views

Trouble figuring out a fail2ban log error message: “iptables -n -L INPUT | grep -q 'fail2ban-SSH[ \t]' returned 100”

Here is my jail.local rule for ssh: [ssh-iptables] enabled = true filter = sshd action = iptables[name=SSH, port=ssh, protocol=tcp] logpath = /var/log/messages maxretry = 5 Here is what my ...
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1answer
30 views

Iptables redirect HTTP traffic to proxy

I have a local HTTP proxy running, if I configure my browser to go through it works perfectly but I would need to leave the browser configuration blank and only redirect the traffic to the proxy with ...
3
votes
1answer
64 views

Firewall: allow all traffic from sources authenticated via. an open ssh connection

I'm looking for a way to avoid the editing of the firewall rules all the time on test and dev servers. I don't want to open up all ports. So I thought maybe there is a way to allow all traffic from ...
1
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2answers
41 views

ftp server in passive mode at private subnetwork

I have following configuration: FTP client (public_IP1) => internet => Firewall(Public_IP2) => FTP server (10.10.12.171) I have following iptables rules at Firewall: DNAT tcp -- 0.0.0.0/0 ...
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0answers
40 views

How to split traffic through two different network adapters based on TCP port in OS X

I have a scenario where we will be using a Mac to stream video content to an RTMP server. This RMTP service provides 2 ingest URLs so that you can upload the same video content twice and have ...
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1answer
13 views

what version of iptables implemented -j CT?

I'm setting a firewall config for different distros/versions and I need to setup NOTRACK for DNS traffic. On CentOS 7 (iptables v.1.4.21), I need to write like this: -A PREROUTING -p udp -m udp ...
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0answers
30 views

Investigating connectivity issue

I'm trying to set a up a new service on a server that is running apache, however it seems like incoming traffic on that specific port is blocked, although I do not understand why. On the first server, ...
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1answer
34 views

Iptables DNAT working in my own network, but not through VPN

For some reasons I need to switch a server ip to another ip, in order to be seen by another computer elsewhere through vpn. So I'm using iptables (didn't know any of that until yesterday) and testing ...
2
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1answer
19 views

Restore rules from output of `iptables -S`

I have a bunch of rules dumped with iptables -S: -P INPUT ACCEPT -P FORWARD ACCEPT -P OUTPUT ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT -A INPUT -p ...
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2answers
61 views

SSH works but tunneling or SFTP doesn't. Why?

since 2014 I've got a server from SoYouStart, with Centos 7. It worked perfectly, but now I had to install again the OS. Now I'm configuring all the services to work again. I need to connect to the ...
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0answers
4 views

Connection interruptions on Debian router, possibly due to excessive duplicate ACKs? [migrated]

I have a Debian server as a house router, which for a year has been working flawlessly. However, I recently moved and switched service providers from FiOS to Comcast, and possibly as a result am ...
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0answers
13 views

How do I set up my iptables to allow web traffic to my Spring Boot application?

I am trying to host my Spring Boot application on Arvixe's VPS Lite. No CPanel, just command line. When I spin up my Spring Boot app and navigate to the server's IP address, I see the ...
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1answer
58 views

Cannot open port 1337

I am struggling with iptables firewall to open port 1337 externally. My iptables file looks like this: *nat :PREROUTING ACCEPT [0:0] :INPUT ACCEPT [0:0] :OUTPUT ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] ...
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0answers
27 views

PHP FTP Pasv mode on CentOS 7

I need help with connecting to a FTP server and using the passive mode. They told me I need to open ports 20, 21 and 5000-5100 range. I've got a virtual machine running CentOS 7 on a dedicated server ...
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0answers
20 views

iptables, redirecting all ingoing connexion

I have this iptables conf on my linux mint... What does it mean ? Chain INPUT (policy ACCEPT) target prot opt source destination ACCEPT all -- 13.37.42.0/24 ...
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0answers
11 views

PSAD / removed iptables block

I'm pretty new to PSAD but eagerly getting into it to have a safer installation. But some understanding is missing I've had yesterday the following notification : [psad-status] removed iptables ...
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0answers
24 views

iptables, multiple vpn with selective routing, unable to forward incoming ports

First of all, forgive my incompetence! I have a Linksys EA6900 with Tomato by Shibby v.129. I have set up 2 OpenVPN clients and successfully configured iptables so all traffic by default is routed ...
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2answers
42 views

Using same port for http/ ssh on two ip's [closed]

How could use two diferent services using the same port on two diferent IP addresses? Example: IP 1 : 192.168.10.10: Service: Http Server Ports: 443 IP 2 : 192.168.10.11: Service: SSH Server ...
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0answers
21 views

Iptabels Port Forewarding Issue

I am trying to forward requests on eth0 (192.168.1.110 port 9600 tcp) to the same port on 192.168.250.2 (reachable through eth1 (192.168.250.150)). This is so that I can leve a preconfigured Raspberry ...
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0answers
7 views

how do --queue-num iptables work?

Relation to --queue-num iptables Example iptables -t nat -A PREROUTING -p tcp --dport 80 -j NFQUEUE --queue-num 30 Explanation The --queue-num option specifies which queue to use and to ...
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1answer
40 views

Multiple TAP devices on OpenVPN Server

So we have a number of clients that have their own VPS instances which we host via Proxmox. The clients servers are all behind a NAT firewall and we forward ports per client request to our various ...
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0answers
8 views

how to port forward to server + tunnel specific hosts route though openvpn client on tomato [migrated]

Running Shibby Tomato v130 on an Asus RT-N66U. My goals are the following With Transmission running on the router have all torrent traffic route through an OpenVPN client also running on the ...
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1answer
43 views

NAT TCP/UDP Connections With iptables on AWS

So I've got 2 instances on AWS set up so I can SSH into them directly (A, B) from my home machine C. But I want to set up box A so that I can forward certain UDP and TCP connections from it to box B. ...
-1
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1answer
27 views

ruleset iptables- user defined chains [closed]

I am very new in iptables. Learning to use them. I got a hang of some basic commands from https://help.ubuntu.com/community/IptablesHowTo. However, I didnt find good explanations of examples of a ...
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0answers
31 views

Very basic nginx configuration failing

The following is my nginx configuration: user www-data; worker_processes 4; pid /run/nginx.pid; events { worker_connections 768; multi_accept on; } http { server { listen 80; listen ...
1
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0answers
80 views

How to simulate network partitions on windows? [closed]

Working on a project which implements a clustering algorithm. One important property of the clustering is to respect guarantees when face a network partition. To prove that clustering works I need a ...
0
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0answers
126 views

squid 3.5.3 with ssl bump

I have configured squid as transparent proxy with ssl bump configuration and using store id to cache youtube Squid 3.5.3 Ubuntu 14.04 Issue is my http sites are working but I cant see https website ...
0
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0answers
36 views

Strongswan: Connection established but one way data transfer

Posting Updated: 26.06 11:22 I'm trying to use a rasperry pi on arch linux as strongswan ikev2 server for my windows phone 8.1 smartphone. I would like to use a client certificate for authentication. ...
0
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1answer
43 views

Delaying packets with libnetfilter_queue

From my Raspberry Pi configured as an access point, I set the following rules: sudo iptables -I FORWARD -p tcp --sport 25 -j NFQUEUE --queue-num 0 sudo iptables -I FORWARD -p tcp --sport 80 -j ...
2
votes
1answer
51 views

iptables blocking some of the traffic on ports 80 and 443 when it shouldn't?

A web server I'm administering shows weird iptables denials from IPv4 addresses on destination port 443, despite HTTPS traffic being explicitly allowed. Port 80 is also allowed in the same rule, but ...
1
vote
1answer
25 views

OpenVZ Host Node showing up in traceroutes

I've installed SolusVM as a Master server that will host OpenVZ containers on a fresh install of CentOS 6.6 What i am now noticing is that if i traceroute one of my containers IP addresses i see the ...
0
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0answers
33 views

Proxy/Gateway/Router server for specific ports only

Sorry, i don't know the correct term for this type of server. English is not my primary language. This is what i want to do : I am migrating my already running web app to Google compute engine (My ...
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votes
1answer
45 views

Setup Tunnel via ssh and use it's Internet for VPN clients

I have two VPS centos 6.6 x64 with Public IP addresses example:1.1.1.1 and 2.2.2.2 VPS with 1.1.1.1 is a VPN server I Need to connect 1.1.1.1 via ssh to 2.2.2.2 so My VPN clients on 1.1.1.1 can Have ...
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votes
1answer
22 views

When adding an IP address drop rule to IPtables it converts it to a domainname/url. Why?

So I have been playing around with IPTables and bash scripts to auto detect bruteforce attacks on my server (averaging about 50 per day minimum - is this normal?). My server logs these attacks for me ...
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0answers
14 views

Hashlimit rule blocks my server

I am using an nginx as a proxy on port 9883 to forward all the requests to an apache server running on the same machine, on port 8888. I am using the following iptables rule to decrease the chances of ...
0
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1answer
38 views

Forwarding all traffic coming into eth0 on host to eth1 on LXC container

I'm trying to monitor all the traffic coming into my computer using software running in an LXC container. The software on the LXC expects to be monitoring eth1. Thus, I would like to Create an ...
1
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0answers
29 views

Get Original Destination Port From iptables

I would like to create a local server that acts as a proxy for all trafic, but how would I determan the original ports when using iptables to rederect the network traffic. I need this for when the ...
1
vote
1answer
34 views

Rate-limiting & dropping natted packets, EXCEPT for 5 local networks

Basically, I am trying to rate-limit requests to a mailserver at the firewall level, but whitelist several company-owned IP ranges. I can whitelist one IP addresses range, but not several, because of ...
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0answers
20 views

I cannot ping my server on PPTP vpn?

I have made a client server PPTP vpn connection on ubuntu. I can connect but cannot ping or ssh from my client to server or vice versa. IP tables server side #!/bin/bash # Set defaults. iptables -F ...
1
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0answers
35 views

Fail to redirect requests to specific url to localhost

I have a server that listens on http://localhost:3000 and I want to forward all requests to http://api.lingualeo.com/addword from Chrome extension (some JSON data) to http://localhost:3000. What I ...
0
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0answers
15 views

Centos 5.8 - firewall blocking Virtualizor staff

I run private KVM/OpenVZ hosting and im currently having issues with it. So I opened a ticket with virtualizor and they say they cant access the VNC connections, but I can. I figured the only thing ...
0
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1answer
55 views

Redirecting HTTP(s) traffic to another server

I am trying to setup a test environment for research/reverse engineering of wireless platforms. I have a router AP broadcasting my network which the hardware I am researching connects to, and from ...