Questions tagged [iptables]
iptables allow creation of rules to define packet filtering behavior. The most reliable way to provide an iptables ruleset in a question is with the output of (as root): iptables-save -c
2,703 questions
0
votes
1
answer
40
views
iptables changes not having any effect [closed]
I was attempting to interrupt a TCP connection on my system, and was altering iptables rules using the iptables command.
Nothing I did seemed to have any effect, though. Inserting and deleting rules ...
- 75
0
votes
0
answers
53
views
Sharing internet connection between 2 pc
I have 2 ubuntu PC connected together by an ethernet cable.
My PC 1 have internet access through another internet cable. My PC 1 also host a DHCP server to give an IP address to my PC 2, because my PC ...
- 1
1
vote
2
answers
102
views
Drop all packets sent to localhost and particular port
I want to drop all packets sent to a particular port. I first tried using firewalld/iptables-nft settings but that failed (maybe they're being processed by the kernel only?).
I succeeded in blocking ...
- 305
2
votes
1
answer
78
views
How to enable internet access for a bridge inside a Linux network namespace?
I've created two Linux network namespaces (ns1 and ns2), and inside each, I have:
A bridge (ns1-br0, ns2-br0)
A TAP device (tap0, tap1) connected to the respective bridge
Each TAP device gets an IP ...
0
votes
1
answer
160
views
Allow specific IP addresses through iptables with Wireguard
I have a number of self hosted services on my home server, running Arch Linux.
Context
A number of these are held in Docker containers (each with their own Docker compose file), though one (Jellyfin) ...
- 26
1
vote
0
answers
53
views
How packet can get lost between filter INPUT and security INPUT chains of iptables?
From this flowchart https://stuffphilwrites.com/wp-content/uploads/2024/05/FW-IDS-iptables-Flowchart-v2024-05-22.png I know that packet goes from the INPUT chain of the filter table right into the ...
- 23
0
votes
1
answer
117
views
route traffic to 127.0.0.1
My scenario:
I have two machines:
192.168.1.1
192.168.1.2
Machine 2 has a ssh server and I created a tunnel in machine 1 such as:
ssh -CfND 7777 [email protected] -4
I ran above command in machine ...
- 11.3k
0
votes
1
answer
52
views
Iptables does not apply drop policy for other ports
I'm running a server where iptables is configured with a default DROP policy and I’ve only explicitly allowed certain ports (e.g., HTTP, HTTPS, SSH on port 22, etc.). Despite never adding a rule for ...
1
vote
0
answers
58
views
Is it possible to route GTP traffic in Linux?
I want to be able to route GTP-U traffic that arrives to my linux through two different interfaces. However, I want to route it using information inside the tunnel: inner ip addresses. My machine is ...
- 11
1
vote
0
answers
39
views
What does the phrase "consider native interface" refer to when the nftables wiki says that xt_bpf match is unsupported
In this list of unsupported xtables features. xt_bpf is listed as one of the unsupported features. The comment says to "consider native interface". But what interface is being referred to ...
- 569
3
votes
1
answer
204
views
Why can't I connect a network namespace to the Internet?
I've seen other answers on this site and read an article and watched a video on the topic, but I still can't connect my network namespace to the outside world.
Setup
I created a namespace named "...
- 133
1
vote
2
answers
117
views
IPIP tunnel between two docker containers on separate servers
Thank you in advance for your attention to my question and your help.
I have a rather specific task. I need to set up an IPIP tunnel between two Docker containers located on different physical servers....
- 11
0
votes
1
answer
166
views
Upgraded k8 worker node from ubuntu 20.04 to 22.04. DNS resolution/networking inside pods doesn’t work & pods keep crashing/restarting
I have a k8 cluster based on Ubuntu 20.04
1 master and 3 worker nodes.
I drained one of the worker node. Put kubectl,iptables, kubeadm, kubelet & containerd packages on hold.
OS upgrade to 22.04, ...
0
votes
1
answer
131
views
How to set `iptables` so NTP works while internet access is blocked
I want to configure iptables such that it blocks everything except
Date time synchronization over the internet using NTP and
Access from machines in the LAN.
I wrote the following script:
# Reset ...
- 286
1
vote
1
answer
170
views
How do I use iptables to redirect a port when the destination is my own IP address?
I've successfully redirected incoming requests from port 53 to 3053 using iptables PREROUTING table
I've successfully redirected local requests from port 53 to 3053 using iptables OUTPUT table as long ...
- 349