Questions tagged [nat]
For questions about Network Address Translation (NAT), a method of modifying network address information in IPv4 packet headers.
549
questions
0
votes
1answer
11 views
Cisco Port forward ip nat inside source static … Invalid
This is almost the same question as How to setup port forwarding on Cisco Router running Version 15.2(4)M6. The problem is that the command used in the answer is not available:
ip nat inside source ...
0
votes
0answers
9 views
Hide GKE cluster pods IP address behind single IP address in site to site VPN use case using GCP Cloud VPN [closed]
Currently I am developing nodejs application deployed to GKE cluster in google cloud platform. This application will need to call 3rd Party API which is only accessible through VPN so that I have to ...
0
votes
1answer
47 views
Why does my enterprise issue me a public IP address instead of just a private IP address?
Let's say I work for a big enterprise organization. When looking at my IP address, I notice that it is not a private IP address but is instead a public IP address.
What are the benefits of ...
0
votes
2answers
53 views
NATTing a server address
I need help writing NAT rule for this use case: I want to be able to connect to an local IP as though it's the remote server IP. e.g. port forwarding.
I don't have access to the firewall on the remote ...
0
votes
1answer
21 views
Cisco NAT - Overload PAT and Static nat from one inside to two outside interfaces
i have following setup
Cisco ISR4k Router with one inside LAN interface and two outside Interfaces.
---- WAN1 (NAT outside)
LAN (NAT inside) -- ISR4k |
...
1
vote
4answers
65 views
port address translation
I was reading about different type of NETWORK ADDRESS TRANSLATION (NAT) techniques from a book, and was reading about a special type of NAT that is called port address translation, and it's known that ...
0
votes
0answers
21 views
Cisco: NAT overload does not work on Serial point to point interface /32 address on Cellular modem
I have a LTE modem installed in a Cisco 1921 that is able to connect to the carrier network and ping out sucessfully from the router, however NAT hosts are not able to connect to the internet.
There ...
1
vote
1answer
53 views
Destination NAT on Cisco ISR
I know how to perform regular overload PAT in my lab running
sh ver
Cisco IOS XE Software, Version 16.03.09
Cisco IOS Software [Denali], ISR Software (X86_64_LINUX_IOSD-UNIVERSALK9-M), Version 16.3.9, ...
0
votes
2answers
34 views
IPSEC between two offices with SAME local networks. How should I do nat? [duplicate]
I have two spokes with same local networks and want to do IPSEC between them.
When I try to ping 172.17.214.111 from 192.168.5.0 (from right side to left side) I see packet on Cisco router and I see ...
1
vote
1answer
65 views
PAT with multiple VLAN
I've set up a network with 4 VLAN, 3 VLAN configured PAT on it and 1 VLAN configured STATIC NAT. The router is acting as the DHCP server. Outside of my router I have another router acting as "the ...
0
votes
2answers
32 views
Two PC on the same LAN, communicating the same Server
Assume that we have 2 pc on the same LAN,
local IP of pc1: 192.168.1.5
local IP of pc2: 192.168.1.6
Now suppose that both pc1 and pc2 wants to connect to a server on the internet,
we all know that the ...
0
votes
0answers
8 views
DMZ host is not reachable from LAN [duplicate]
I have a pfSense firewall with WAN, LAN and DMZ interfaces. A server is residing in DMZ with private ip 10.0.0.2. Therese a 1:1 NAT in WAN interface that is mapping a public ip X.Y.Z.213
to 10.0.0.2, ...
0
votes
1answer
22 views
Public IP address does not work in internal network [closed]
I have configured port forwarding to my system from the router configuration menu, when I try to access the public IP address in the internal network it does not respond but it is accessible outside ...
0
votes
2answers
54 views
Possible typo in Tanenbaum's book about NAPT
From what I have understood from multiple sources (web and other books) about the concept of NAPT (also called NAT overload or IP masquerading in Linux environment), if there is a scenario like the ...
1
vote
3answers
73 views
Static NAT and PAT
I have two private IP addresses, want to make them NAT to 203.0.113.0/2 public IP address.
WAY 1 : Static NAT (2 ip addresses NATted to one by manually)
WAY 2 : PAT (Router gives port number ...
0
votes
0answers
34 views
CMTS (DOCSIS 3.0) with CGN (CGNat)
For a new project/building I am working with the CMTS model MA5633-XB10 by Huawei.
The usual way is done by implementing two DHCP servers in the same VLAN, from which the CPE gets the private IP ...
2
votes
2answers
111 views
What happens when a NAT router reaches its 65,535 connection limit to a specific destination?
If a company of thousands of end points all try to access a specific destination (let's say google.com), then the maximum TCP connections it can have in total is limited to 65535 connections, based on ...
0
votes
1answer
423 views
pfSense 1:1 NAT Not Working
Next year, if I have the money for it, I want to get a dedicated server (either from Hetzner or OVH) and some IPs (maybe like 16 IPs). The server will have Proxmox and VMs will get their network ...
3
votes
2answers
523 views
Why is symmetric NAT called “symmetric”?
After searching a while, I'm still not able to find a logical explanation on why it is called symmetric NAT.
Where lies the link between symmetric NAT and that each request is mapped to a unique ...
0
votes
2answers
95 views
Cisco router on a stick with public ip wan (ISP)gateway
I am trying to create a router on a stick with an outside facing sub-interface with a public IP from an ISP. I have tried to configure NAT and routing but I just cant get to ping the internet. I'm ...
0
votes
1answer
74 views
Issue w/ Cisco router and failed NAT and static default route
I have a cisco router that is using a VRF to support a site to site VPN tunnel. I have added a second network to the router for non-VPN standard internet use. My problem is that my default static ...
1
vote
2answers
85 views
How Does Network Address Translation Work Initially at the End Point Router
I have come across a question that I can not seem to get a quality answer to. I understand how NAT works when a reply packet is received and how it is mapped back to an internal IP address from the ...
0
votes
1answer
69 views
Static port forward 1194 to VPN server behind Cisco router
I'm trying to setup a VPN server behind a Cisco router which is my main internet gateway. I've set it up as shown in the attached picture. The problem I'm observing is that zero packets with a ...
0
votes
2answers
40 views
Why doesn't NAT drop packets with spoofed public source IP?
As I read on Section 4.3.8 of this page https://www.manrs.org/isps/guide/antispoofing/,
The following code:
ip nat inside source list INSIDE pool OUTSIDE overload
will translate packets with a ...
2
votes
1answer
31 views
Cisco ASA NAT/PAT Multiple WAN IPs
I'm trying to setup a NAT / PAT in ASA 5520, I'm able to do so very well when the Public IP I want translated to Internal host is configured on the Outside.
Question is the ISP provided 1.1.1.1/30 ...
0
votes
1answer
40 views
Why does Network address translation (NAT) need Port Address Translation (PAT) if IPs are different in the internal network?
For example, there are several servers in the local network 192.168.0.1, 192.168.0.2, 192.168.0.3, etc.
They are connected to one public IP.
Why does NAT also assign ports to each local IPs that are ...
0
votes
2answers
60 views
Do NAT devices need to have private IP addresses?
If a NAT's job is to create mappings between internal ip/port pairs and external ip/port pairs with one Internet-routable IP address, does a NAT need a private IP address for itself? I think one ...
0
votes
0answers
148 views
Debug ip nat in IOS XE
I used to use debug ip nat in IOS to show NAT translations happening. On a Cisco C1111-8P running IOS XE, this command does not exist anymore:
router#debug ip nat
% Incomplete command.
router#debug ...
0
votes
0answers
13 views
What's the difference between “IP NAT Inside Source” and “IP NAT Inside Destination” commands in Cisco routers? [duplicate]
As much as i know both of this commands translate source address of packets that travel from inside to outside and destination address of packets that travel from outside to inside,so what's the ...
2
votes
0answers
60 views
Cisco ASA static nat one-to-many from interface address to object-group
Syntactically, the following set of statements is valid (at least as of 8.3):
interface Ethernet0/0
nameif OUTSIDE
ip address 192.0.2.1 255.255.255.0
interface Ethernet0/1
nameif INSIDE
ip ...
2
votes
1answer
63 views
Prevent static NAT to respond to ARP requests
We are trying to merge 2 networks with overlapping IP spaces: This is the configuraiton so far:
interface Tunnel1
description VPN Port CompanyA
ip vrf forwarding LAN
ip address 172.18.0.79 255.255....
1
vote
1answer
25 views
Segregated network - managed switch or router?
I have 3 pc connected to a switch that is connected to a bigger network. I want those pc to live in their network and don't expose their ips.
(in this very moment the scope is accomplished using a pc ...
0
votes
2answers
64 views
When a packet is received, how does it know which internal machine to send it to?
I am familiar with ARP and routing, but I think I am failing to put two and two together here. On an IPv4 packet we have the source IP address, which allows any router to send the response back to the ...
0
votes
2answers
61 views
Why can some people use public ip address to access a server from an internal network with the client device within the internal network
As the title suggests. I find it mind breaking to think how network architecture can differ to allow/not allow using public IP address to access a server within internal network from within the ...
0
votes
0answers
10 views
Ipsec connection and nat only one site [duplicate]
There are two companies and two of them connected to each other with İPsec vpn. Company A has a server and company B want to reach to company A server. Which company need to configure nat on its ...
0
votes
0answers
54 views
NAT translations showing up on router but end-host cannot ping ISP
When an endhost (192.168.40.3) on VLAN 40 pings 172.27.47.30 (NL1-BS fom ISP1), a request timed out message is given. However, the "show network translations" on R1 has a translation entry even though ...
1
vote
1answer
44 views
When is NAT Masquerading required?
I'm learning about NAT Masquerading and I'm a bit confused about when you would want to Masquerade. I've seen examples of using an interface for a VPN tunnel and how something like that on a router ...
2
votes
0answers
32 views
Packets lost with correct TCP sequence number. Is it possible?
I'm analysing some communication issues that we have between a server (SCADA) and remote terminal units (RTU) that we have in the field. The communications are IEC104 protocol which use TCP/IP.
The ...
0
votes
0answers
99 views
NAT overload and access to web resources
I have really bizarre problem in clients network.
Clients have access to the internet via NAPT - I'm using several public ip addreses for this purpose. (I'll change ip addresses for obv reasons)
ip ...
0
votes
3answers
150 views
Single-homed connection to ISP without NAT feature
Is it possible to connect my private network to the ISP router without a Network Address Translator (NAT) feature enabled on my router? As I understand, in a single-homed scenario connection to ISP, ...
0
votes
1answer
35 views
Is performance worse routing between two vlans on one interface than routing between two NICs with no vlans?
I have a Linux router with one interface that is connected to a switch in port 2.
Port 2 on the switch is a member of vlan2(ISP) and vlan3 (office devices).
My router is currently routing between ...
5
votes
3answers
2k views
Does NAT violate end to end argument?
Does NAT violate end to end argument?
What does end to end argument means in this context?
2
votes
0answers
32 views
How to configure an ACL on ASA when the inside source IP address is translated by NAT? [closed]
I don't know how to configure an ACL when inside source nat is enabled.
In my example, I want to realize bidirectional communication with TCP port 30000 between 172.16.100.100(inside) and 10.10.10.10(...
1
vote
1answer
539 views
Active Directory and DNS over NAT
I'm planning to apply the network address translation on a router between hosts and AD/DNS server in an organization. It seemed that this scenario is complicated for a private network.
The topology ...
3
votes
3answers
372 views
BGP and NAT Not working
I have an odd issue with BGP+NAT. I have 2 separate routers and 2 different ISP's.
Topology looks like this:
ISP1--BGP--> RTR1 \
\--OSPF-- Palo Alto Firewall-- Internal ...
0
votes
1answer
142 views
LAN to WAN IPv4 address mapped to LAN server through NAT Rules or other
I need to set a rule that allows me to connect BOTH from OUTSIDE the LAN (from the "internet" to the Internal server at IPv4 address 10.64.0.50 via port 22, by running ssh://1.2.3.4 -p 22; AND
From ...
0
votes
1answer
31 views
NAT on the endpoint
NAT is normally performed on the router to translate addresses from one network's address space to another's. Is there ever a reason to perform NAT directly on the endpoint instead?
For example, if ...
2
votes
1answer
165 views
How does NAT ensure that every machine has a unique public IP?
I am trying to understand the distinction between public and private IP addresses in IPv4 networking. The picture I've been told has some problems with it, so I would like to present it here and ask ...
1
vote
1answer
98 views
How does a DNS response reach a client behind a NAT?
How does a DNS response reach a client behind a NAT? I'm talking about DNS queries using UDP for transport with a server that is not in the same network as the client.
Does the NAT correlate the ...
1
vote
0answers
164 views
Static PAT using Cisco ASA 5506 in cisco packet tracer [closed]
ciscoasa(config)#interface GigabitEthernet 1/3
ciscoasa(config-if)#nameif inside1
INFO: Security level for "inside1" set to 0 by default.
ciscoasa(config-if)#security-level 100
ciscoasa(config-if)#no ...
