All Questions
529
questions
42
votes
1
answer
34k
views
iptables vs route
What's the difference between these two tools?
Can anybody tell me what the main workflow of networking behind Linux (in relation to IPv4 packet filtering, NAT and IP routing table) is?
- 1,280
33
votes
2
answers
34k
views
What's the difference between iptables "state" and "ctstate"?
I saw this iptables snippet in a different Super User answer:
iptables -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
...
- 5,836
17
votes
1
answer
13k
views
How to transparently tunnel a port from IPv4 to a remote IPv6 device?
At home, I am connected with an IPv6 address and additionally, my provider provides a NAT-like setup through which I receive a public IPv4 address that I share with other customers (the reason being ...
- 599
11
votes
2
answers
43k
views
Using iptables to redirect ip address
I have the requirement on a Linux system where the Linux device is using RSYNC to sync data to another Linux machine. This is working fine at the moment, however I need to move one of the machines to ...
- 603
9
votes
1
answer
56k
views
iptables duplicate traffic to another ip
This blog post has a template iptables rule to forward traffic, to and from the router to another ip address.
iptables -t mangle -A POSTROUTING \
-d [IP to spy on] \
-j ROUTE –tee –gw [IP ...
- 405
9
votes
3
answers
5k
views
Iptables forwarding port/s to a external IP transparently (remote end should see the actual source IP)
The question is simple but I think the answer might not be as I went through countless related topics with no concrete reply.
I wish to forward a port 1234 from x.x.x.x to y.y.y.y (both on internet ...
- 91
8
votes
2
answers
9k
views
Deleting a IP from blacklist iptables
I created a blacklist using ipset and iptables called "blacklist", now i would like to know how i edit "blacklist" to remove or add IP's.
Anyone knows?
- 151
8
votes
2
answers
18k
views
How to allow FORWARDing with firewalld on a Fedora 19 router
I've just installed Fedora 19 and I'm using firewalld instead of iptables, but I'm having difficulty interpretting the new terminology.
I have 2 NICs. One is specificed ZONE="internal" and the other "...
- 261
8
votes
1
answer
10k
views
Will increasing number of rules in iptables slow down my internet
How much impact will the rules have on speed, if we are using match to queue the packets.
- 471
8
votes
1
answer
20k
views
Can ping but can't connect (curl, wget, apt-get, etc.) (rasberry pi server)
Background:
I am trying to set up a rasberry pi server. Everything was going well and my pi could apt-get update etc, until I got the port forwarding to work and ssh to work outside of the LAN. I ...
- 193
7
votes
2
answers
40k
views
How forward packets from network interface to another
My problem is forward packets from eth2 that is my LAN to eth1 that has access to internet, to allow eth2 to access to internet, here my configuration:
auto eth1
iface eth1 inet static
address ...
- 73
7
votes
1
answer
11k
views
How to deliberately introduce a delay for incoming UDP packets
I want each packet (that match iptables rule) to be delayed by some fixed time interval. How to to this?
Preudocode: iptables -A INPUT -p udp <more conditions> -j DELAY --delay 50000 # delay ...
- 17.3k
7
votes
5
answers
26k
views
How to forward traffic using iptables rules?
I am new to iptables and I have been doing Google searches for a few days now without finding a good solution to this problem.
I have computer A with a public ip address (say 192.0.2.1) that can ...
- 171
6
votes
1
answer
11k
views
Two NICs on the same subnet but with different networks?
Description
This is similar to this question, but different:
Linux computer has two NIC. eth0 is statically assigned with an IP. eth1 is assgiend by personnel in the field which could be same IP or ...
- 161
6
votes
1
answer
9k
views
Load balancing with multiple gateways
I have to different ISPs, each on each own network. The main connects via ethernet and the secondary via wifi. The two networks have no relation at all. I just connect to them simultaneously. The ...
- 237