Tagged Questions

Iptables is a module that provides the Linux operating system functions of firewall, NAT and logging of data traveling over a computer network.

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1answer
139 views

How to drop IP packets received on the default route interface when no other than default route is found?

I am setting up a router based on a linux kernel. As expected, ipv4 packets received on the interface used by default route are sent back to the same interface in case no other route is found. Is ...
0
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0answers
800 views

How does iptables masquerading allow to access a different local subnet?

My Linksys router (IP 192.168.1.1 inside a /24 subnet) is connected to my ADSL modem (IP 10.0.0.138 inside a /24 subnet) to establish an internet connection via PPPoE. To be able to access the modem's ...
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3answers
645 views

linux routing outbound port 80 traffic via ssh tunnel, iptables, or a simple route

I have two hosts, A and B. Host A hosts services on port 8080 and has outbound internet firewall rules allowing port 80 and 443 access to Host C. Host B is on the same subnet as Host A. Host B is ...
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votes
1answer
1k views

using iptables to prevent RST related to a specific port

I have a program which uses libpcap to capture incoming TCP SYN packets, these SYN packets are destined for a specific port. But I have no tcp listening socket for that port, so in practice, the OS ...
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3answers
112 views

iptables rules are not in action

I have a iptable rule file, on the INPUT chain I have -A INPUT -i em1 -p tcp -m tcp --dport 54000 -j ACCEPT -A INPUT -i em1 -p tcp -m tcp --dport 30000 -j ACCEPT -A INPUT -i em1 -p udp -m udp --dport ...
1
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0answers
309 views

Advanced QoS on prioritized first packages set by ISP

I have the following problem my ISP (Fibertel from Argentina) accelerates, 'enhances' the first 6.8 megabytes of downstream transfer and it's seems the first 1.8 megabytes of upstream transfer. This ...
0
votes
1answer
100 views

allow redirects with iptables

with the following rules, php can't make a redirect to another file. it's freezes at the point when it gets toheader("Content-type: video/x-flv"); header("Location:" . $VIDEO); or ...
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2answers
1k views

IPtables Rules to Block IP Range

I've applied the following rules from a text file called "iptables.save" to iptables. But to my dismay, I found that the ip address 107.22.26.176 is still able to access my server via TCP. What did ...
0
votes
1answer
522 views

How to allow access to only specific IPs with Parallels VZ built-in firewall?

How can I use Parallels Virtuozzo's built-in firewall utility (called psa-firewall under the hood apparently actually psa-firewall seems to be a seperate Plesk interface - either way, it's basically a ...
0
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1answer
479 views

How can I add the port to iptables rules on centos?

I want to open the port 8040 on my centos, but I keep getting connection refused. This is what I have done: iptables -I INPUT -m state --state NEW -p tcp --dport 8040 -j ACCEPT iptables -I INPUT -m ...
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2answers
304 views

Iptables: Allow Internal LAN to access INTERNET

I have an internal network behind my router on eth0, and I have my router connected to the internet thorugh wlan0. I can't access the internet from inside the lan, how can I fix this? wlan0: ...
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votes
1answer
130 views

Configure IPTables [duplicate]

We have RHEL 5.0 squid proxy in our office. Our LAN is 172.20.12.0 /24 n/w. Proxy ip is 172.20.12.4 /24 . I want to share Internet through proxy. Most importantly: Suppose I have flushed the ...
-1
votes
1answer
569 views

LInux squid proxy

We have RHEL 5.0 squid proxy in our office. Our LAN is 172.20.12.0 /24 n/w. proxy ip is 172.20.12.4 /24 . I want to share internet through proxy. Most importantly: I want to give full access to ...
2
votes
1answer
826 views

iptables status enabled after restart even after disabling

I am disabling iptables on Oracle Linux 6 with these commands. setenforce 0 service iptables stop service ip6tables stop chkconfig—level 123456 iptables off chkconfig—level 123456 ip6tables off ...
0
votes
1answer
703 views

UDP packet and firewall

I notice when I send udp packets from computer A to computer B, B can receive the upd packets correctly but if I send udp packets from computer B to computer A the udp packets are not received A and ...
1
vote
2answers
2k views

unable to connect to localhost:80 after installing nginx

I just installed nginx by doing sudo yum install nginx and I'm unable to connect to it on port 80. I tried stopping iptables by doing sudo service iptables start and was still unable to connect. I'm ...
1
vote
1answer
131 views

iptables simple forwarding setup woes

I have iptables running on a host (acting as a firewall) in a Linux namespace with only one network interface: h2-eth1 (has an IP and MAC address) I have set up my switch to forward all packets to ...
0
votes
1answer
299 views

show interfaces in iptables -L

Is there a way to show the network interfaces via iptables -L in Ubuntu 12.04? When I execute an iptables -L I get an output like this : Chain INPUT (policy DROP) target prot opt source ...
1
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1answer
745 views

Port-Forwarding for Click'n'Load remote usage

I've got JDownloader running on my HTPC and access it via VNC. The problem with Click'n'Load (CNL) is, JD only listens on localhost:9666 for incoming traffic, and the browser applications only send ...
3
votes
1answer
1k views

Linux iptables forward from ip1:port1 to ip2:port2

I connect thought tunnel to other machine like this: ssh user@ip -L2000:192.168.64.88:80 So on my local machine I want to configure iptables that way like I have a "native" access to ...
2
votes
1answer
260 views

Restrict the number of http and https connections from a specified IP address to ten connections per minute

How I can restrict the number of http and https connections from a specified IP address to ten per minute usingiptables commands? I’ve tried this but it is not working: iptables -A INPUT -s ...
0
votes
1answer
2k views

OpenWrt: how to give wlan clients @ 10.x Internet access via gateway @ 192.168.1.254

I want to isolate guests connecting to my Wi-Fi to the 10.0.0.x subnet, while giving them Internet access. The OpenWrt router is at 192.168.1.48 ("wifi" interface has 10.0.0.1) and my gateway is at ...
2
votes
3answers
1k views

iptables - add rules not as root

One of our servers is being hit daily by a large number of spam bots. They're not able to post any spam, but they still try and end up slowing down the server for real users. To counter this, I have ...
2
votes
2answers
353 views

How to send out some traffic via my vpn connection

I had a working setup where I could access all my work resources which are accessed via VPN going via my server previously however at some point recently this stopped working for no obvious reason. ...
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2answers
795 views

How to test IP Tables Rule (Linux Ubuntu12.04)

I wanted to ask how to test IP Table Rules. For example, I have a port number and I want to be sure that it accepts all packets. How can I do it? After I type iptables -L I see that the rule has been ...
0
votes
1answer
961 views

DD-WRT - Host-based forwarding

I would like to know if I can configure DD-WRT router, that operates as the server's network gateway, so support different forwards based on hostname (other than port 80). I've configured ...
3
votes
1answer
1k views

IP forwarding on the same network

I have a raspberry pi that I have put wifi on. I am also using its ethernet connection to bring internet to my XBox 360. I want to bridge these connections AND keep them both on the same network. For ...
0
votes
1answer
251 views

Block brute-force on server with http auth behind cloudflare proxies

My server is behind Cloudflare proxies. I have configured simple http authentication to restrict access to some server resources. I'm trying to block brute-force attacks on http auth with fail2ban. ...
0
votes
0answers
155 views

IPTables masquerading stops working

In a classical SOHO setup I am running a Debian box as router/firewall. For an unknown time now I have an issue, where the MASQUERADING on the output connection (PPPoE) stops working for one of the ...
0
votes
1answer
322 views

Iptables: allow specific ips on specific port

I am trying to allow a few IPs on port 80 and disallow all other from access port 80. Can someone suggest the iptables rules needed for this to occur?
3
votes
0answers
2k views

How do I configure DD-WRT to forward IPSec traffic to an internal server to support a road warrior configuration?

I use dd-wrt as my home router setup and that's been working fine. Now I wanted to figure out a way to be able to use my iPad to set up a IPSec tunnel to my home network while I'm on the road. PPTP ...
3
votes
2answers
3k views

Using iptables SNAT based on source interface and ip address

I would like to change source ip address according to ip address and interface it came in. Let's consider following example: ----------------------------- | | | ...
7
votes
1answer
717 views

Sharing transparently proxied Internet connection with PS3

I am trying to play a Japanese karaoke game on a PS3 but the latency is just horrendous and downloading songs takes forever. One recommendation I got was to turn my laptop into a SOCKS proxy by ...
0
votes
1answer
1k views

DNS resolving broken after installation of bind due to iptables

I successfully configured my web server (Apache, PHP etc.) and blocked the ports I don't need using iptables, which was working perfectly fine. Today, I installed BIND and configured it, which also ...
0
votes
1answer
86 views

Accessing ports remotely

I have a fedora server on a local network which I can access through VNC. I am trying to install a JIRA plugin called Activity timeline, these are both built using Java. When I log into VNC and ...
1
vote
1answer
638 views

set https proxy with squid and iptables

have a Linux as router, eth0 (192.168.0.60) connect to LAN, eth1 (10.100.33.239) connect to Internet. squid works well, I can set 10.100.33.239:3128 or 192.168.0.60:3128 as proxy in web browser and ...
0
votes
1answer
379 views

Port 6667 can't be reached outside of localhost

I've got IRCD-Hybrid installed with the following listen config: /* listen {}: contain information about the ports ircd listens on (OLD P:) */ listen { /* port: the specific port to listen ...
2
votes
2answers
2k views

How to use iptables to connect proxy server

In my company, all http and https must connect to a proxy server, which means we must set proxy in our web browser. Our department has an internal network (192.168.0.xxx). I use a Linux server as ...
6
votes
2answers
259 views

Open up firewall automatically to anybody who has successfully connected via SSH

I have a server which runs a few services. However, for security reasons, I configured the server so that nothing, except for SSH, is accessible from outside. What I'd like to do instead, though, is ...
4
votes
1answer
3k views

How to configure a firewall on Centos using Vagrant and Chef

I've created a server box using Vagrant and Chef and everything is up and running correctly. However, when the box is installed from scratch the default iptables rules are in place and so I need to ...
1
vote
1answer
594 views

Filter multicast from WAN to specified vlan

I'm using ebtables to filter multicast IPTV from my Wireless and Wired Lan. Right now its configured like this: Router ( DD WRT ) VLAN1 (PC Network) VLAN2 (IPTV) I am using this command: insmod ...
1
vote
0answers
478 views

tc/netem and iptables: Delay traffic only from specified ip and port

I have a Ubuntu Router with 2 network interfaces. eth0 is the private network and eth1 is the internet. What I want is the following: All packages (mostly udp) comming from a specified private ip ...
1
vote
1answer
1k views

iptables: How to redirect port in Red Hat Linux (RHEL)?

I'd like to forward port 80 to 8080. So I tried to edit /etc/syscongfig/iptables: -A PREROUTING -t nat -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 8080 But got: # service iptables restart ...
1
vote
1answer
812 views

iptables routing marked packets from router to PC and routing them back to router

I'm trying to do deep packet inspection on HTTP packets. The purpose of this is to collect HTTP payload data and then create some proxy/cache-independent reports. Following this, the idea is to ...
1
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0answers
144 views

How to unblock jabber on TI ADSL router with iptables

I have old but reliable Texas Instruments ADSL router. Board AR7RD; BUILD=061005; VERSION=3.7.1 If that matters... One thing that bothers me is that it somehow blocking my jabber (Pidgin ...
2
votes
1answer
584 views

IPTables - unknown error 4294967295

I've moved an old Slackware 11 installation from a physical PC to a virtualized in ESXi. Everything seems to work fine except for one rule in iptables, namely the row: iptables -t filter -I INPUT -m ...
4
votes
1answer
2k views

Access Apache server running in Fedora guest VirtualBox from host

I have trouble accessing Apache server from host. I’ve Fedora 15 VM VirtualBox installed on Windows 7. Within this VM I have Apache server running and working fine within the guest. Not sure what ...
2
votes
1answer
208 views

amule, Fedora 14, iptables

I need to set iptables rules for aMule, but I am not sure which one are the right ones. Googling around, I have seen something like: iptables -I INPUT -p tcp --dport 4662 -j ACCEPT iptables -I ...
1
vote
2answers
668 views

How to “shut off” all networking on Linux from bash?

I'd like to write a bash/shell script that "turns off" the machine's ability to communicate over it's network card, effectively shutting down all networking. From the command line: # To turn all ...
0
votes
1answer
501 views

how to telnet redirect ip and host using iptables

I try to telnet from PC 3 To PC 1 and it's redirect to PC 2 PC 1 : 192.168.0.1 PC 2 : 192.168.0.2 PC 3 : 192.168.0.3 i have command like this in PC 1: iptables -t nat -A PREROUTING -p tcp -d ...