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Questions tagged [iptables]

An application that allows a user to configure the tables provided by the Linux firewall. iptables is succeeded by nftables as of 2014.

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What's wrong with this outbound iptables firewall? [migrated]

I have a mail server which I'd like to secure by only allowing OUTBOUND connections on the various ports it uses. The inbound rules are working fine - they are handled by the VM host. I've not been ...
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2answers
83 views

How are my iptables rules circumvented?

I'm using ufw on a debian server and apparently an attacker is able to circumvent the filtering rules. ufw uses iptables. The server host http and mail services, and has an ssh port. I use a non-...
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1answer
509 views

Fully transparent proxy

By default mitmproxy will use its own local IP address for its server-side connections. What I want instead is mitmproxy to use the client’s IP address for server-side connections. The following ...
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2answers
90 views

Why can't iptables drop arp requests

I was trying to hide my laptop from my phone's network scan app. The app is using arp requests to find devices on the network. I tried everything on iptables. It doesn't work, even if i set all the ...
6
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1answer
471 views

SSL MITM on the WAN side of my router

Hi I would like to try to sniff a typical CWMP conversation that my router does to his Auto Configuration Server (see TR-069 crash course: https://www.iol.unh.edu/sites/default/files/knowledgebase/...
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134 views

Experimenting with SSLStrip+ on the same machine

I am trying to play around to understand how SSLStrip+ works by: $ cat /proc/sys/net/ipv4/ip_forward 1 $ sudo iptables --flush $ sudo iptables --flush -t nat $ sudo iptables -t nat -A PREROUTING -p ...
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1answer
22k views

Is it safe to disable connection tracking in iptables?

While reading about NOTRACK target of raw table in iptables, I encountered an article suggesting that for certain traffic you could (or even should) disable connection tracking. The two examples were: ...
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1answer
204 views

watch DNS queries while using OpenVPN.-

I want to monitor/sniff the DNS queries I make while I'm using a VPN connection with my OpenVPN client. My initial motivation was to check if I'm leaking DNS queries; then using this page it seems I'm ...
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1answer
3k views

Connection to ports 2000 and 5060 successful despite filtering

I run my own (Ubuntu based) router and have iptables configured to drop all incoming packets by default. To my surprise, running an nmap scan (from the WAN side) shows two open ports related to VOIP: ...
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4answers
1k views

SIP UDP request breaking through iptables

I have been investigating a few instances recently where SIP UDP traffic has been somehow evading the ruleset defined in iptables leading me to suspect that there is a hole in our rules so i'm looking ...
7
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1answer
218 views

System-Level Network Security (Packet Classification and etc.) - SELinux and Libnftnl

I read that Libnftnl is a userspace library providing a low-level netlink programming interface to the in-kernel nf_tables subsystem and it uses NFTables. Since it's a kernel related topic, at the ...
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0answers
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Are parts of my system susceptible to IP based malicious attack even with effective IPtables rules?

Yesterday I installed Cent OS 6 and had to flush the default IPtables rules (IPtables -F) in order to access a web app via my browser. Having very little experience with Linux/Network security this ...
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2answers
207 views

Dealing with the dangers of self-hosting a webserver?

Assuming for a self-hosted webserver: the webserver only hosts a static html website iptables is used to reject every IP except a few known ones only Port 443 is forwarded and the website requires ...
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1answer
285 views

Building a malicious captive portal

So I'm trying to build a malicious captive portal but I'm stuck on the part where you need to know stuff. Anytime a HTTP request comes in, everything works fine. However, when an HTTPS connection ...
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1answer
125 views

Is iptables and vpn tunneling enough? [closed]

What is the best approach to secure connection between two devices over the internet (public IP)? if there is a firewall on my public IP address deny access all incoming connection, can the hacker ...
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1answer
38 views

What are the methods by which an attacker can distinguish between DROP on IPtables and a Nullroute or non-allocated IP?

Let's say we have a server set up with set to: iptables -P INPUT DROP Without any other rules on the input chain. Ignoring accessibility issues outside of physical server access, what are the ...
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1answer
1k views

How to block traffic coming from an “public” WiFi hotspot and going to the LAN (iptables)

I followed this tutorial (http://elinux.org/RPI-Wireless-Hotspot) for an Wifi Hotspot in the guesthouse. This is working fine, but every device on the WiFi network can reach any LAN device in the LAN ...
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64 views

SSL Strip failing [duplicate]

I am trying to learn how SSL strip is used. I have Kali Linux machine as attacker, a windows machine as target, and an access point. All my machines are physical machines and not VMs. I've done the ...
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1answer
1k views

ARP spoofing with Scapy. How does Scapy reroute traffic?

Background: I understand that in order to ARP spoof a victim in a network using Scapy, we need to send ARP reply packets to the victim and the gateway router with the correct destination and Source ...
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1answer
2k views

Can't connect to fake AP with airbase-ng

I use kali-rolling on a virutal machine and I try to set up a fake access point using airbase-ng, but my devices won't connect to it whatsoever. My steps are: I put my wirless adapter in monitor mode ...
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0answers
105 views

Intercept data after sslstrip

I am able to use sslstrip successfully as shown here https://moxie.org/software/sslstrip/ What I want to do though is be able to use sslstrip with another proxy/script to modify requests/responses ...
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180 views

Exploit vulnerabilty in embedded Linux network stack to disable iptables

I own a D-Link DCS-7110 HD POE network camera. It features an apparently iptables based access list configuration where you can allow/disallow certain networks and addresses from accessing the camera....
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IPSec and traffic mirroring [closed]

I have a VoIP server on which several SIP clients are connected to through IPSec tunnels. This is kind of an automated attendant so I both have RTP and SIP signalling flows. I need to be able to ...
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1answer
307 views

What is the most secure communication between firewall, and DMZ

I have 2 virtual machines. (Vmware esxi 6) They are both opensuse 42.3 (tumbleweed) Firewall (iptables,ipset,dhcpd,dns only) mail/web server. (apache,dovecot,postfix) The web server can not ...
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0answers
1k views

Creating a rogue AP with Kali Linux

so i have for the last 2 days going through this task of setting up a Rogue AP on my Kali linux running in my VM.... i am using the 64bit version and the wifi adapter is TP link TL WN722N, so my ...
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3answers
691 views

Does blocking an IP with IP Tables protect you from a DOS (not DDOS) attack?

I am fairly new to network security, and I just learned about the Fail2Ban framework you can use for automated exploit detection/prevention. It says that you can protect yourself from DOS attacks by ...
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1answer
308 views

Security Onion VMWare + OpenWRT IPTables Mirroring

I'm trying to set up SO in my home network to lab and see if I can monitor all ingress/egress traffic from my SOHO router. I don't have a switch with SPAN ports, or a network tap so I'm using OpenWRT ...
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1answer
127 views

What is the iptables rule to block all https traffic except to a single ip?

I'm trying to configure a microservice for my web application, which is hosted at ip address X.X.X.X. The microservice should only accept https connections from this web app. I've tested the ...
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2answers
3k views

What are the security implications of net.ipv4.conf.eth0.route_localnet=1 / route_localnet?

sudo sysctl -w net.ipv4.conf.eth0.route_localnet=1 What are the security implications of route_localnet?
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171 views

Debian automatic dnsbl

Watching requests log, I see some IPs, considered Black List. For example: 91.224.217.74 - - [06/Dec/2017:11:12:54 +0000] "GET / HTTP/1.1" 200 10951 "-" "curl/7.17.1 (mips-unknown-linux-gnu) libcurl/...
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1answer
303 views

PREROUTING interfaces SSL MITM

I'm trying to make SSL MITM attack but do not really understand how to configure my interfaces to preroute traffic. I have a laptop, connected to a PC via Ethernet, the PC is connected to the rest of ...
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1answer
390 views

Can iptables be hacked / circumvented

We currently have a server that blocks all connections using iptables, and we have to whitelist an IP expressly in order to be able to access the server remotely. Essentially, the first rule allows ...
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1answer
665 views

How to prevent ARP poisoning with hostapd and iptables?

I have a raspberry pi and hostapd and iptables are running on my pi. However iptables cannot block the wifi clients from communicating with each other, thus I cannot prevent them from sending out ARP ...
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1answer
238 views

Iptables DROPS SSH after port knock rules, but nmap shows it as OPEN

I setup port knocking rules on CentOS 7, iptables as follow: -I INPUT -p tcp --dport 1 -m recent --set --rsource --name KNOCK1 -m limit --limit 5/min -j LOG --log-prefix "knock 1" --log-level 7 -I ...
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1answer
131 views

Captive Portal Security Measures

I am currently working on a Captive Portal solution, which can be distributed in an device that has an ethernet and wlan port. In short, I use iptables to restrict access to all devices unless they ...
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1answer
206 views

What ports should I filter on a default Magento installation

I have recently installed a Magento on Ubuntu 14.04 on Digital Ocean and I'm wondering what ports should I filter to keep it safe. Well, actually the question should be: what ports I keep open to the ...
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1answer
448 views

SSL Strip on Fedora24

I want to perform a MITM attack on my own network, and followed several tutorials on how to use sslstrip, iptables and arpspoof. But every time I perform the attack, I lose the connection on the ...
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5answers
2k views

Firewall demo - iptables

I have to make a demonstration about firewalls in my class as a student(university). It should be implemented using iptables on Linux. I am reading all the theories around them but I can't figure out ...
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0answers
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How should I manage wireless connections if using iptables?

I am implementing some modest iptables on xubuntu 17.04 and came across this blurb from IptablesHowTo Ubuntu WARNING: Iptables and NetworkManager can conflict. Also if you are concerned enough ...
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1answer
763 views

MitM-Position with bridged network and iptables

I'm currently trying to get my setup to work. [ victim ] --- [ mitm ] --- [ net ] IPs: net: 10.0.0.0/24 victim: 10.0.0.1 mitm: 10.0.0.2 gateway: 10.0.0.254 setup: ip l a name br0 type bridge ip l ...
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1answer
300 views

How to block an application with iptable which use random port

Scenario: My goal was to allow TeamViewer to connect to my home workstation from my laptop only. So I have tried to bind my laptop's MAC with an IPtables rule as following, [arif@arif:~]$ sudo ...
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1answer
2k views

Networking in Qubes OS [closed]

I've started recently to use Qubes OS and I want to set up a virtual IDS and IPS in separate VMs, but I can't figure out how the communications between different VMs works here. Each VM should be ...
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1answer
980 views

Iptables as vpn killswitch but access to internal network

currently I'm using iptables as a kill-switch for my VPN connection. Therefore I only have one rule : -A OUTPUT -o eth0 -m owner --uid-owner 1000 -j DROP everything else is accepted. Now the ...
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1answer
792 views

Is a Captive Portal Wifi AP as insecure as an open unencrypted Wifi?

As far as I understand, the captive portal is implemented by some sort of iptable firewall rules. Since there is no handshake established during the initial association with the AP(As no passphrase is ...
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0answers
177 views

Why is Skype traffic not passing through the NAT table of the PREROUTING chain in iptables?

I have successfully performed a MITM attack and have managed to view the HTTP/HTTPS packets of the victim passing through the nat table of the PREROUTING chain of my iptables.(using -j LOG) However, ...
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1answer
1k views

Nmap - Intense vs Quick result

I inherited a small network and currently am assessing its security performance. I started port scanning a host (lets call it Weirdo) in that small network and from my perspective, it seems that that ...
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1answer
638 views

inetsim installation perlipq/libipq error

I am trying to install inetsim on Ubuntu 14.04 where I have been following instructions from several blogs and the inetsim.org documentation itself at: inetsim download and installation Now one of ...
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3answers
126 views

How to prevent DDoS to cause stored data inconveniences?

Let's assume there are no vulnerabilities in the application layer, one disk, and no physical firewall (just iptables rules in the server itself), hence in this case all the DDoS attack does is to ...
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1answer
136 views

Which chain of the iptables receives the sniffed packets

Host C is using wireshark to sniff packets from Host A to Host B. I am able to see those packets from wireshark but I am not able to find them in the PREROUTING chain of iptables. When Host C ...
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1answer
694 views

How to prevent ICMP redirection produced by a man-in-the-middle

How can I prevent my route to be redirected with redirecting ICMP packets from a man-in-the-middle? I am specifically looking to avoid someone using ettercap with the -M icmp option. From man ...