All Questions
42
questions
0
votes
0
answers
100
views
How to simulate a NAT network in Ubuntu host with iptables and iproute2?
I want to simulate NAT network mode of virtual machines without using any vm-specific tools. The detailed goals are the following:
The VMs have internal network IP 10.8.20.0/24
The physical nic eno1 ...
- 101
0
votes
2
answers
1k
views
iptables -t nat seems not working properly
I'm working on Ubuntu 20.04.
I set the following iptables rules:
sudo iptables -t nat -A POSTROUTING -d 192.168.10.162 -j MASQUERADE
sudo iptables -t nat -A PREROUTING -p tcp --dport 445 -j DNAT --to-...
- 157
0
votes
1
answer
5k
views
How to port forward my ubuntu 22.04 using iptables
Do you know how to gives iptables rules to my machine in order to allow trafic from my public interfaces(wlp3s0) to my private interfaces(lo). Kinda with this topology: 192.168.1.1:80 => 127.0.0.1:...
user1598709
0
votes
0
answers
323
views
Home Router NAT Network configuration Ubuntu 20.04
I have Ubuntu 20.04 desktop and home router and I trying to open ports to have an acces from internet.
Here is interface info
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN ...
- 1
-1
votes
1
answer
5k
views
Ubuntu 20.04 gateway, iptables NAT and port forwarding
i am in a maze, i try in vain to setup the rules to be able to acces from internet my internal web server (192.168.12.10).
at home, i have an Ubuntu 20.04 gateway (192.168.12.1) with two interfaces :
...
- 1
0
votes
1
answer
4k
views
Bad argument in iptables NAT command
I am trying to do a DNAT rule in iptables if the packet with source address 192.168.86.212 and destination address 192.168.86.212 then change the destination address to 172.217.5.100.
sudo iptables -t ...
- 137
1
vote
1
answer
572
views
Network routing and port forwarding problem
I have 2 networks (graph in link below)
A: 10.0.0.0/24
B: 192.168.1.0/24
In network A, all devices are connected via a switch. Some devices provide certain services such as ssh or access to a database ...
0
votes
1
answer
6k
views
Link-local 169.254.x.x address assigned at boot despite static IP on 20.04 LTS [closed]
I have been struggling to setup my Ubuntu machine as a simple 2-NICs router with NAT, trying to stick to most recent recommended methods, namely netplan for the NICs and ufw for firewall and for ...
- 17
0
votes
1
answer
505
views
IPSEC site-to-site overlaping networks
we have two sides connected over ipsec using strongswan. both machines ubuntu 16.04 servers. the issue is both end subnets are overlapping. we have tried all possible iptables scenarios to map ...
- 49
1
vote
1
answer
3k
views
Ubuntu Server - "Virtual" Network Interface with Internet Access
I have an Ubuntu 18.04 server with one public network interface (eth0). I'm trying to create additional "virtual" network interfaces that will also be able to access the internet with NAT rules set up....
- 11
1
vote
0
answers
156
views
Permanent redirect on Ubuntu for Mosquitto bidirectional MQTT traffic
I need to permanently redirect all traffic in the short term from an old mosquitto server to a new one until the firmware updates have been completed on the edge devices. I tried using iptables as ...
- 11
0
votes
1
answer
6k
views
How to use IPtables for load balancing in gateway
I have 3 NICs. NIC1 and NIC2 are used for internet connections
an LAN is used for intranet connection.
I want to balance the load to ISPs using ip tables. As I am a noob, my crude attempt is given ...
- 329
1
vote
1
answer
4k
views
iptables setup for routing
I want to setup my ubuntu computer to route packets. Therefore I've read several tutorials which always had many rules to add to iptables.
I finally found out, that the only rule needed (given that ...
- 113
1
vote
1
answer
3k
views
Routing between 2 wired interfaces without using NAT features
I have two internal networks (I do not want/have Internet access) where I connect my Ubuntu 14.04 (with eth0 and eth1 network interfaces). From eth0 (network 192.168.0.0) I connect another PC1 ...
- 13
0
votes
1
answer
2k
views
iptable matching rule for STUN/TURN traffic
I am looking for finding TURN/STUN packets coming on a 443 port.
According to the TURN RFC, Bytes 46 to 49 are TURN packet magic cookie '2112a442'. Here is the screenshot from wireshark where I found ...
1
vote
0
answers
767
views
16.04 iptables NAT weird behavior keeps working when removed
root@p10:/proc/net# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.3 LTS
Release: 16.04
Codename: xenial
OVH Public Cloud Server, on ...
- 399
0
votes
0
answers
436
views
lxd container with openvpn server does not apply iptables nat rule
I'm trying to setup openvpn on one of my lxd containers to allow access to the container network. The server seem to work and I can access (ping) containers which have a static route pointing to the ...
- 866
1
vote
0
answers
56
views
how to view the interfaces for each connection in the nat table?
I've used cat proc/net/ip_conntrack to view all the connections related to the NAT table on the device. But this doesn't give any information with respect to the interface used and the type of nat for ...
- 11
2
votes
1
answer
6k
views
ubuntu iptables NAT & Router & Port Forwarding
I would like to forward the ssh port from ubuntu-fw (firewall) to ubuntu-server1.
| Internet | --- | Router (hardware) | --- | ubuntu-fw | ---- | ubuntu-server1 |
Router (hardware): Fritz-Box
...
- 121
5
votes
2
answers
20k
views
NAT using iptables on Ubuntu 16.04 doesn't work
I used to use Ubuntu 14.04 trusty for our NAT server (build on Google Cloud Platform), but recently I tried to use the Ubuntu 16.04 xenial.
I configured perfectly same as I've done in 14.04, but it ...
1
vote
1
answer
1k
views
Ubuntu: VPN kills NAT
Output: Wireless Info Script
Connection is ISP router (DHCP) - eth0 192.168.1.91 - wlan0(NAT/DHCP) 192.168.5.1
I'm using hostapd to bring up the AP, /etc/network/interfaces to create interface and ...
- 23
1
vote
2
answers
2k
views
Forward packets from bonded LAN interface to WAN
I am not able to route packets between the lan side of my ubuntu server and the wan side. I'm looking for some assistance. I have 5 ethernet ports on my server - 1 onboard (eth0, used for wan) and 4 ...
- 23
0
votes
1
answer
899
views
Cant connect an ESXI host behind an ubuntu NATusing Vsphere
I have 2 NIC's on ubuntu ;
eth1 (pci-e based net. card) > WAN (router) and
eth0 (onboard) > server (onboard) (no cross cable)
so what I want is to access both ubuntu (vnc and ssh) and esxi server (...
1
vote
0
answers
122
views
Keep the same port number for forwarded packets
I have the following IPSEC setup:
LEFT (IPsec) <===> MID (PPP) <=ppp=> RIGHT (IPsec+PPP)
All running Ubuntu 14.04 LTS.
MID communicates with RIGHT in PPPoE (marked ppp).
Now...
IPsec servers ...
1
vote
1
answer
140
views
File copy fails over Ubuntu Gateway using NAT
I have managed to successfully set up NAT on my Ubuntu 14.04.4 machine so that my computer acts as a gateway for a computer connected on the internal interface (eth0) to the external interface (eth1)....
- 111
0
votes
1
answer
6k
views
Port forwarding with DNAT not working
I want to forward my local port 2221 to a remote machine (192.168.2.100), where ssh listens on port 2222.
Connecting to the remote machine works:
ssh -p 2222 192.168.2.100
[email protected]'s ...
- 21
1
vote
0
answers
5k
views
Setting up NAT forwarding using iptables on ubuntu server 14.04
I have a server with 2 ethernet interfaces(em1 and em2). em1 is the internet facing interface(192.168.16.113) and em2 has a static address(10.1.1.100) connected to a switch. I have configured the ...
- 41
0
votes
1
answer
135
views
DNAT redirecting to specifc port is not working
I want to redirect ssh by port using DNAT, and i do try to ssh it through the command > username@IP_ADDRESS:10003, and I got this message:
ssh: Could not resolve hostname IP_ADDRESS:10003: Name or ...
- 329
2
votes
1
answer
1k
views
configure iptables to redirect traffic to a specific IP address
I have just began using iptables. I have a server with a public ip address
(A.A.A.A) wich is hosting a Virtual Machine (B.B.B.B) on
local network.
I want to redirect all inbound traffic on the port ...
- 63
2
votes
1
answer
3k
views
NAT port forwarding using iptable doesn't work
I have a server with Ubuntu Server and a Xubuntu virtual machine on it, virtualization software is virt-manager.
Ubuntu Server IP: 172.16.63.140
Xubuntu Virtual Machine IP: 192.168.122.4
I can do
...
- 221
0
votes
1
answer
190
views
How to use my ubuntu server as router?
+---+
eth1- *.1.6| S |
=========| |
|PC1|private net --------------------
| |=============...
- 155
0
votes
1
answer
484
views
How to setup IPTABLES for logging/monitoring usage while using a DSL with a dynamically assigned IP
I am trying to set up a system to do NAT and other iptables-stuff (like logging, firewall, monitoring, etc.). The ISP provides a dynamic IP address and the DSL modem does NAT.
I have the following "...
- 129
29
votes
2
answers
114k
views
What's the difference between PREROUTING and FORWARD in iptables?
I am trying to understand how this system works and I have problems to understand the difference between using NAT PREROUTING or filter FORWARD.
From what I understand, the PREROUTE can send the ...
- 403
0
votes
1
answer
1k
views
Setup NAT on Ubuntu 14.04
I'm trying to insert my desktop between an appliance and the rest of the network to monitor the traffic coming off of it due to some security concerns. I'd like to setup NAT so that the devices behind ...
- 7,309
5
votes
0
answers
10k
views
Using Ubuntu 14.04 as router with iptables, clients can't go online. Probably DNS issue, iptables setting needed [closed]
CORRECTION 3: SOLVED! I needed to add the the official DNS server of my departement's VLAN as DNS to the clients.
I've read through a large number of posts about iptables issues when using Linux as ...
- 150
1
vote
0
answers
35
views
NATing ports selection using hardware detection
I have a linux box to be used as a router with a wlan port in AP mode. The internet input to the board may come from either an eth port (WAN mode) or another wlan port. There is also VPN running that ...
- 11
1
vote
1
answer
2k
views
Dnat prerouting does not work on Ubuntu 14.04 [closed]
I've got a Ubuntu 14.04 server used as firewall, router, dhcp, dns and proxy. Everything works properly from inside to the internet, but the forwarding from outside to the inside network doesn't work.
...
- 17
9
votes
2
answers
2k
views
How to disable NAT for IPv6 (NAT66)?
The current Ubuntu LTS does not support NAT tables for IPv6 (i.e. there is no ip6tables -t nat), and I'm fine with that, in fact, a NAT-less environment is the "core" of my networks.
But, the next ...
- 829
0
votes
2
answers
2k
views
Ubuntu 12.04 LXC nat prerouting not working
I have a running Debian Wheezy setup I copied exactly to an Ubuntu 12.04
While the Debian setup runs flawlessly, the Ubuntu version dies on the prerouting to containers ( or so it seems )
In short:
...
- 193
2
votes
1
answer
890
views
NAT forwarding not working
I tried to set up forwarding from eth0 to wlan0 in ubuntu:
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -F
iptables -F
iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE
iptables -A ...
- 121
1
vote
1
answer
700
views
redirect traffic from 2 Ubuntu external NICs to specific internal hosts
I am having problems redirecting incoming traffic to 2 external facing interfaces on my Ubuntu 12.10 server to 2 separate internal hosts. I am able to redirect incoming traffic on my eth0 just fine to ...
- 59
2
votes
1
answer
5k
views
Log destination IP with iptables
I want to log destination IP addresses in my Ubuntu router. I have two network cards
eth0 - 10.0.101.254
eth1 - 10.0.101.253
10.0.101.254 is the GW for all hosts on my network.
The router works ...
- 145