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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2answers
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How does TLS traffic impact firewalls?
If I have an open port on a firewall it means that I can receive traffic on that port. If it's unencrypted I assume that the raw data is just allowed through.
If TLS is being used, does firewall ...
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0answers
6 views
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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2answers
98 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 ...
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0answers
135 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
208 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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0answers
37 views
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
208 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 ...
0
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1answer
288 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 ...
1
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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 ...
2
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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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0answers
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
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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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 ...
1
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0answers
69 views
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 ...
11
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1answer
513 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 ...
7
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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 ...
0
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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 ...
5
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3answers
693 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 ...
4
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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 ...
0
votes
1answer
132 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 ...
2
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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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0answers
172 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
394 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 ...
2
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1answer
239 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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0answers
182 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....
0
votes
1answer
133 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 ...
0
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1answer
210 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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0answers
65 views
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 ...
1
vote
1answer
773 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 ...
0
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1answer
302 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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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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1answer
310 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 ...
2
votes
1answer
794 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, ...
9
votes
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
137 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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2answers
132 views
Using IPTables over a network [closed]
I recently found out how to "block" an IP address from your computer, with this command:
sudo iptables -A INPUT -s 210.1.193.49 -j DROP #Blocks 210.1.193.49 from your computer
I was wondering, how ...
2
votes
1answer
130 views
Which set of rules is more restrictive when allowing SSH in iptables?
I have seen two set of rules to allow SSH communication:
Set A:
iptables -A INPUT -p tcp --dport 22 -j ACCEPT
iptables -A OUTPUT -p tcp --dport 22 -j ACCEPT
Set B:
iptables -A INPUT -m state --...
1
vote
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 ...
3
votes
2answers
2k views
MAC filtering the internet traffic?
I was trying to build a firewall where in the access to my LAN from internet should be allowed only if it matches the predefined MAC address of the device i.e,. MAC filtering, but later i found out ...
0
votes
1answer
99 views
Network Defense- White listing IPs/Ports
If I had a typical home user machine (google, email, youtube, no ssh/ftp, etc...) that had a dynamic iptables white-list that was dynamically updated with IP addresses that have been legitimately been ...
6
votes
1answer
472 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/...
3
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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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2answers
211 views
how to block pop up with iptables
Although I have enabled the pop up blocker in firefox, there are many websites that are able to circumvent this feature. (for example movie streaming sites like kinox.to). My question is not really ...
3
votes
1answer
1k views
Setting up a fake AP - problem with iptables and DNS server
Im trying to set up a fake AP using aircrack-ng suite, DHCP server & iptables.
After creating the fake AP:
airmon-ng start wlan1
airbase-ng -c 11 -e "freewifi" wlan1mon
running iptables ...
0
votes
1answer
984 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 ...
0
votes
1answer
4k views
Iptables rules to prevent IP Spoofing
We had following below iptables rules that exist in our web front-end boxes to prevent IP Spoofing:
-A INPUT -s 255.0.0.0/8 -j LOG --log-prefix "Spoofed source IP"
-A INPUT -s 255.0.0.0/8 -j ...
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 ...
2
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0answers
592 views
Is there anyway to customize the --reject-with answer in the iptables? [closed]
Is there any way to customize the answers that can be given with the --reject-with option of the REJECT of IPTABLES?
I was reading in the man of the IPTABLES the part of the REJECT and the only ...
