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Questions tagged [masquerade]

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Sendmail does not masquerade the hostname.domain combination

My MASQUERADE settings looks as follows... dnl # Also accept email sent to "localhost.localdomain" as local email. dnl # LOCAL_DOMAIN(`localhost.localdomain')dnl dnl # dnl # The following ...
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UDP Broadcast not being masqueraded

I have a VM in Proxmox with an IP (192.168.1.10) coming from a bridge. I have masquerading on to enable it to communicate with my network: -A POSTROUTING -s 192.168.1.0/24 -o host_inteface -j ...
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125 views

Port forwarding while preserving the source IP address with firewalld

I signed up with a new ISP and they dont provide me with a external IPv4 address. Ive set up a virtual server (S) (that has an address) to relay all my stuff to my box at home (B) using a wireguard ...
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1 vote
1 answer
99 views

How to block a internal host from the internet with firewalld by MAC address

I am trying to stop some hosts on the network from going outside/calling home. So I have 2 zones. [root@eagle ~]# firewall-cmd --get-active-zones external interfaces: enp2s0 internal interfaces: ...
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2 answers
117 views

Masquerade / firewalld target : impacts on filtering?

I opened a question here, but as I found some new elements, I prefer to open a new one. Here is my situation, that can be reproduced: Fresh Centos7 OS. Configuration of two interfaces eth1 and eth2 ...
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149 views

How to replace MASQUERADE with SNAT for outgoing connection in iptables

I have a scenario like following : PC1(192.168.1.100) ---> iptables(192.168.1.1 / PUBLIC_IP (ens160) ) ---> PUBLIC_SERVER ( SOME_IP) I want to let my PC1 to connect to a specific port of ...
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Linux Kernel IP Forward activated, firewalld is bypassed?

On a Linux Centos7, I have some traffic that is routed with static routes from one interface to another. I did notice that with firewalld activated, both interfaces added in a zone, and nothing ...
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3 answers
221 views

why MASQUERADE SNAT can block localhost connection?

I observed a weird behaviour on linux: First, I clean all routes and iptables rules: ip route flush table main ip route flush table default ip route flush table local iptables -P INPUT ACCEPT iptables ...
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1 vote
1 answer
472 views

Unwanted masquerading in docker container

Although I have not added any iptables rules on the host or the two containers, packets from one docker container are modified and given the IP of the docker network gateway: Container 1: bash-5.0# ip ...
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-2 votes
1 answer
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Debugging my NAT setup

I'm trying to get a raspberry Pi3 to forward traffic coming in to wlan0 further upstream via eth0, but it is failing for some reason I cannot see. Hopefully someone else can spot the issues. Pi3 state:...
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PortForwarding eth0 to ppp0

I have a RaspberryPi which connects to the internet on eth0 which has static IP, I have installed Squid and I have also enabled 1694 port on my Mikrotik router to be forwarded to 3128 port on my ...
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1 answer
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Mikrotik - NAT over 2 ports - cant get it to work

I have a problem with setting up NAT over two ports in separate LANs (there is no internet involved in this). Situation description: Problem is that our PBX. It has some crazy network setup with loops ...
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2 answers
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Using nftables to forward HTTP(s) traffic to VM guest without masquerade

I am currently in the process of setting secure as possible KVM based server. The VM host should be more or less invisible to the internet and only VM guests running single services should be exposed. ...
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1 answer
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NFTables: is it possible to forward traffic without masquerading it?

I have a remote server (B) that forwards certain incoming traffic to another port of a different server (A, dest). With "masquerade" I only see traffic coming from the forward server (B), is ...
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1 answer
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Can't get linux router/iptables masquerade working

Hope someone more clever than me could help because I am out of ideas... We want to create (in openstack) a router that will...route (haha) trafic from one network to the other. Simple. This is what I ...
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2 votes
2 answers
2k views

Why an iptables NAT does not happen in the network namespace separated transparent proxy setup?

I'm trying to setup transparent proxying networks on my host. Real Client and Proxy targets are containters but in this experiment I use netns (network namespace) separated envinroment. To redirect ...
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1 vote
0 answers
385 views

Dual-way NAT forwarding using IPVS?

I want to replace iptables(8) with IPVS for a TCP reverse proxy which involved dual-way NAT. My current setup using iptables is functionally equivalent to a userspace forwarder (like socat(1)). It ...
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Is there a way to limit Src Ports in IPtables masquerading

I have the following chain setup by kube-proxy in my iptables on all my Nodes. Chain KUBE-POSTROUTING (1 references) target prot opt source destination MASQUERADE all -- 0.0.0.0/...
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1 vote
1 answer
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How to preserve external IPs through gateway to keep using Fail2Ban

I have a CentOS 7 box with 2 NICs acting as a gateway; one NIC is connected to the internet while the other NIC is connected to our LAN. The first NIC belongs to the 'external' zone of firewalld, it ...
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1 vote
1 answer
284 views

Need correct iptable rules for NAT instance to prevent loop back for private subnet EC2 instance outgoing traffic

My AWS architecture has a public subnet having a NAT instance. It forwards the traffic on certain ports to my EC2 instance hosted in a separate private subnet. sudo iptables -t nat -A PREROUTING -...
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1 vote
1 answer
902 views

How to NAT private IP to public IP through virtual LAN in centos 6

Guys i am having an issue with NAT on centos. In my LAB Centos is configured as a router. I want to run my local system (example: 192.168.1.45) apache server on live IP (example 112.100.4.34). This ...
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2 answers
147 views

Any drawbacks to to using nat MASQUERADE with no source constraint (in a typical simple VPS setup)

Situation: A VPS already serving web pages via nginx. Now I am adding OpenVPN for roaming devices to this VPS. One installation for the VPN guide suggests adding this MASQUERADE rule - iptables -A ...
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0 votes
1 answer
3k views

Unable to NAT TFTP traffic because iptables is not forwarding the return connection to the client despite TFTP helper creating an expectation

The Problem I have a TFTP server (Machine 'S') and a TFTP client (Machine 'C') on different subnets. They are connected via a router( Machine 'R'). All 3 machines are Debian 9/Stretch. The router is ...
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1 vote
1 answer
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Windows 98 routing issue [closed]

I have following network setup: Main router connecting to internet, with LAN address 192.168.1.254 Secondary router connected to first router, with LAN address 192.168.2.1 I have two PC's connected ...
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Redirecting masqueraded traffic through TOR

I am trying to configure AP with redirection incoming traffic through TOR. My AP now has 2 network interfaces: eth0 - have internet access (192.168.1.92/24) wlan0 - intranet, without internet (10.0.0....
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0 answers
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How to use private IP address in router machine [closed]

I would like to use 192.168.11.1, but use global IP address againt my will. I would not like to use global IP address in router when Im usging web browser and client applications. How do I do ? Now:...
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1 answer
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Linux IP-tables Forwarding loose Source IP on access.log [closed]

Team, We have configured IP tables with forwarding request coming on eth1(public IP x.x.x.x) interface to other server. We are able to forward all requests but problem is loosing origin public IP(...
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1k views

How do I get a PPTP server to have a static IP address per client?

I have an Ubuntu 16.04 server running a PPTP server. The server is running fine, the pptp.conf file has the following: localip 10.1.1.2 remoteip 10.1.1.3-252 The chap-secrets file is setup to give ...
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Router with DHCP in Centos 7? Where can be an error in settings?

I'm looking for a thorough tutorial on how to configure: Modem (77.77.7.76) -> Centos 7 -> 192.168.1.0 -> DHCP -> 100 host Please look at my configuration. Two network interfaces: enp0f0 enp0f1 On ...
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-1 votes
1 answer
660 views

firewalld masquerade control [closed]

for various reasons I have had to adopt CentOS 7 as a public facing firewall machine implementing NAT and a few other bits and pieces. Seems easy enough. My basic strategy is to assign the outside ...
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2 votes
0 answers
178 views

natting ftp server inside lan with gateway port 1965

I want to forward access on my gateway (internal ip: 192.168.4.4) from external port 1965 to a FTP server inside my lan (192.168.4.2) So in other term, someone accessing with FTP my gateway:1965 will ...
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1 vote
0 answers
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Same network, two interface cards, hosts behind different networks

Can anyone help with this? I have a gadget that has a fixed IP address 10.0.0.2, which I cannot change. It needs to talk to my laptop, which in turn needs to talk to the internet. My main network ...
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2 answers
6k views

How to Access a host behind a server over VPN (IP Forwarding)

I have a Ubuntu server (172.10.200.11) and many remote terminal units with simcards and each individual simcard operator using different IP pool such as 10.57.0.0/16 for OP-A, 10.112.0.0/16 for OP-B, ...
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1 vote
2 answers
2k views

Is it possible to masquerade a packet on a bridge?

I have a container which has an incoming VPN. A connection into that container will be assigned the 192.168.10.10 IP. The virtual NIC of the container has an IP of 10.10.10.1 and a gateway (on the ...
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3 votes
0 answers
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avoid packets being treated as "martians": is this thinking correct?

I have a cable connection with a Linux-based router. The router has two physical interfaces: enp1s0 (dhcp from cable provider) enp2s0 (192.168.1.1) with masquerading on enp1s0. then, I have an ...
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1 vote
1 answer
344 views

NAT Masquerading second container network

I have 1 public IP, and would like to share internet connection to LXC containers running Centos (in this setup) the host runs proxmox (debian based). If I understand correctly, i need NAT ...
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1 answer
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netperf + iptables masquerade -> network unreachable

Why iptables rules pass netperf TCP_STREAM test through, but break UDP_STREAM? I have a network: +---------------+ | | [client]--[NAT]--[server] On the NAT, I have added the ...
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2 votes
1 answer
703 views

Why IP masquerade (source NAT) in linux kernel fails to set source IP on high packet rates

I am trying to test throughput of the standard linux NAT. I have setup the following virtual network: [192.168.42.5] <--> [192.168.42.2:192.168.35.2] <--> [192.168.35.10] The middle host ...
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1 vote
1 answer
348 views

DNAT for connecting a subnet via proxy to the internet

DNAT for connecting a subnet via proxy to the internet I want to connect a server in a subnet to the internet via a proxy-server. But I can’t ping a host on the internet (www). Actually the subnet-...
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1 vote
1 answer
1k views

ICMP ECHO REPLY is not being SNATed correctly

I am trying to provide L3 connectivity between two remote LAN networks (10.0.0.0/24, 10.0.1.0/24) using OpenVPN with the following setup: +----------------+ +---------------------+ +----------------...
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3 votes
1 answer
2k views

CentOS 7 ip masquerade for internet access

My CentOS XYZ has two network interfaces: iface1 136.136.10.10 is connected to gateway 136.136.10.1 iface2 192.168.10.1 is connected to private network XYZ can access the internet through gateway ...
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3 votes
0 answers
799 views

forward vpn traffic from tun1 to tun0

I've been banging my head on this for a while and gave up trying to figure it out. My knowledge about routing and iptables is just too limited to understand this it seems. I have configured a split ...
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0 votes
1 answer
674 views

iptables DNAT to external IP without masquerading does not work

On server 1.1.1.1: iptables -t nat -A PREROUTING -p tcp --dport 20000 -j DNAT --to-destination: 2.2.2.2:20000 iptables -t nat -A PREROUTING -p tcp --dport 20000 -j LOG --log-prefix pre20k iptables -...
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1 vote
1 answer
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Using DeamonPortOptions to fix DKIM signing with genericstable masquerading

I'm sending mails from my debian server with sendmail. I want to be able to send mail with multiple domains using masquerading with genericstable. I am signing the mails with OpenDKIM but because ...
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2 votes
0 answers
617 views

How to monitor the bandwidth per each iptables masqueraded device [closed]

Question: Which tool could I use to monitor and break-down in real-time which bandwidth is routed by iptables to which computers? Context: I have a linux box masquerading about 15 devices to ...
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0 votes
1 answer
2k views

Keep source port for outgoing packets

I have 2 interfaces eth0(192.168.0.1) and eth1(10.1.1.15). And I do nat for all packets in this way. iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -j MASQUERADE Now I want to keep source port ...
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6 votes
1 answer
11k views

Proxmox Nat Networking Issue

Definition I have installed Proxmox 3.2 and i am trying to configure a virtual machine as a communication server that handles all traffic and forwards them to the nodes with private ip. I ...
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1 vote
0 answers
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Unable to setup wlan0/ppp0 bridge

Don't know how many hours/days I have into this 'simple' problem, but I'm stuck... What I'm attempting to do is connect an eth0/wlan0 bridge to a ppp session (in other words share a ppp connection to ...
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241 views

Simple MASQUERADE NAT between 2 VM

I'm on a cloud service and I'm trying to set up NAT between two VM. I've never experienced issues in this simple step, but this time is different and I'm near to give up. The first VM had two ...
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200 views

NAT answers instead of remote host

Currently I have VPN client access set up on OpenSuSE 13.1 server to third-party remote Cisco VPN IPSec server. VPN Server is set up to provide access for a host only and to provide access for a local ...
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