12
votes
1answer
17k views

Mirror Port via iptables

I have a dedicated Linux (Debian 7.5) root server, with a number of guests set up. The guests are KVM instances, and get network access via bridge-utils (NAT, internal IPs, use the host as a gateway). ...
1
vote
1answer
96 views

iptables is treating traffic from different hosts differently in spite of rules

Something spooky is happening here and I don't know how to fix it. Summary: traffic that appears identical to tcpdump is being treated by iptables differently. Details below.Test setup:device ...
6
votes
1answer
7k 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 ...
5
votes
2answers
20k 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 ...
2
votes
1answer
563 views

Traffic not being forwarded through NAT

I have a router which provides internet access using NAT, and a client Linux box (A) which is connected to this router on eth0.This Linux box also has a wlan interface, wlan0; what I would like is ...
30
votes
3answers
49k views

No idea what is listening on port 80 in OS X

I'm on OSX Mountain Lion 10.8.3, and I've freshly rebooted my Mac.I want to start a service (like Apache on port 80), but there is already something going on with port 80:telnet localhost 80...
7
votes
1answer
5k views

Ubuntu IPTables allow only allow 1 country

So I've been looking around on the net for a script that will drop all traffic to all ports except the http(80) and https(443) ports, and then only allow traffic on all other ports from country x (...
3
votes
3answers
18k views

Source Based Policy Routing & NAT (DNAT/SNAT) aka Multi WANs on CentOS 5

Originally posted at Unix and Linux but nobody was able to answer it, so m migrating the question here:My question is regarding Source Based Policy Routing on CentOS 5 with 2 WANs plus a LAN (NAT) ...
8
votes
1answer
4k 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 ...
4
votes
1answer
5k 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 ...
2
votes
2answers
1k views

Iptables port mapping from two PCs to one

We have 3 PCs, two of it are connected to internet (both of it have 2 NIC)PC1:eth0 - 1.0.0.1 (external IP)eth1 - 172.16.0.1 (internal IP)PC2:eth0 - 1.0.0.2 (external IP)eth1 - 172.16.0.2 (...
3
votes
1answer
614 views

iptables reject tcp-reset on loopback

I am trying to check how a software would behave if there is a network failure. That software is using tcp send() and recv() to communicate.Previously I was making the software communicate by ...
3
votes
2answers
3k views

Transparent tunnel between interfaces on remote hosts

I need to make a solution which will work as a network switch with two ports: one port located in one country and second port is in another country.+------------ Virtual switch --------...
1
vote
1answer
374 views

How to add virtual NICs to my linux PC, so that they expose their MACs to ISP's domain?

I have learned how to add virtual NICs to a guest system in VirtualBox, just using Shared Adapter, then all the virtual NICs and my host's NIC will appear as real NICs to the ISP.So I guess there ...
1
vote
1answer
78 views

Iptables NATforwarding setup

I have 2 Virtual machines with CentOS7:Networkcard : Intern network IP 192.168.1.10 w/ GW: 192.168.1.254 enp0s3 (Client1) (NO DIRECT CONNECTION TO INTERNET)Networkcard : Intern network IP 192.168.1....

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