Questions tagged [nat]
For questions about Network Address Translation (NAT), a method of modifying network address information in IPv4 packet headers.
621
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P2P Connection with Aggressive Firewall [closed]
I was testing my P2P app with a particular firewall.
If I originate the packet first, the firewall is letting it through and the peer sees it and then they are able to start communicating.
However, in ...
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5
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83
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Are there any methods of differentiate between a single computer and a NAT router?
As far as I know, a traffic from a NAT router should appear similar to traffic from one computer with a single IP address. If you do not have any access to a network (let's say you are an ISP), can ...
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2
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If there's a NAT-capable gateway between WAN and a switch, why is a switch helpful?
To preface this question, my question is somewhat related to what I'm trying to understand as the difference between layer 3 switches and routers. The main difference between the two is that layer 3 ...
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If your ISP already has a gateway, why do you need another gateway with NAT to come before a layer 3 switch?
Please bear in mind that I am learning and have never set up a network with routers and switches myself. Also please bear this is sort of going to be loaded question because there are multiple layers ...
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connect two private network using pfsense
I have two pfenses (say p1 and p2) in two separate networks. Each has a public IP. There is an internal network on each side (say n1 and n2). I want to connect these two networks through these two ...
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Can somebody help me understand this static NAT example
I have the following example:
From my understanding of static NAT the client makes a request on the inside global address of a resource, in this case the webserver. (http://209.165.201.5). The request ...
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in Twice NAT, why cant external network be advertised to private network?
This is from the NAT RCF:
The following is a description of the properties of realms supported
by Twice-NAT. Network address of hosts in external network are unique
in external networks, but not ...
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51
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Best way to configure for port forwarding
I am using a Peplink Balance 30 router. Right now I have only one public IP. I have set up the LAN for 192.168.8.1. I have five devices on the LAN side, including two Ubiquiti Rockets and three IP ...
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Is it possible to set maximum 32 PAT translations per global ip address?
So basically I'm trying to configure a cisco router (c7200) to use PAT with a pool of global addresses, and each global address should only support a maximum of 32 private addresses.
I've been ...
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IPTables how to nat 10.8.a.b to 10.0.a.b? [closed]
The problem -- Translate 10.8.a.b to 10.0.a.b ?
I have a VPN setup to a bastion host. I'm attempting to map 10.8.0.0/17 into 10.0.0.0/17 so that the IP address 10.8.1.1 gets mapped to 10.0.1.1 in my ...
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Public IP Configuration which has a private gateway
I bought a public IP from my ISP and they provided me with the following details.
WAN IP :10.129.69.157
LAN IP : 196.188.173.32/30
How do I configure this on my side ?
The told me to do configure as ...
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4
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Do I get any security benefits by NATing a network that's already behind a firewall?
I'm deploying a new network for IOT devices, this new network will be behind a firewall. I've been suggested to also get the network natted to further improve security. Does this really add any ...
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Why is it necessary to configure an ACL when configuring Dynamic Nat?
When configuring Dynamic NAT, why is it necessary for us to also create and specify an access list which dictates what kind of traffic should be translated?
Couldn't we simply skip this step, so that ...
- 617
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Could we use an IP address in our network that does not fall into the RFC 1918 range?
RFC 1918 specifies 3 ranges of IP addresses as private
10.0.0.0/8
172.16.0.0/12
192.168.0.0/16
So in a real network, only these IP addresses could be used? What if I assigned a host on the network an ...
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Sophos XG Virtual Host Load Balancing
I own a Sophos XG cluster (v18) and I need to balance http/https
traffic at lvl 7, by virtual host, among different servers.
To be clear: I need to balance the vhost www.example1.com between 2 servers ...
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How to NAT a unicast address to a broadcast address?
I have a 800-Series router connected in the following configuration:
Port GigabitEthernet7 is connected to an external server (192.0.2.251) that sends unicast UDP to destinations 192.0.2.42:45100 and ...
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Cisco ASA not accepting external traffic without NAT configuration
First of all, I am quite newie in the cisco world, so this could be some easy stuff that I'm missing.
My first problem is trying to understand why a Cisco ASA5585 does not show traffic while doing a ...
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When a new entry in the NAT table is created and an entry in the NAT table is removed?
When using TCP, is a new entry in the NAT table created when a connection is made? and is an entry in the NAT table removed when a connection is closed?
If I am correct, what happens if both ...
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How can a port be both be used to identify a private IP, and also to connect to a specific service?
Sorry if im asking something nonsensical, im still trying to wrap my head around these terms.
Heres my understanding
NAT is the process of translating a private IP to a public IP, lets make an exaple ...
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Is Port Forwarding a type of NAT? [duplicate]
I am reading about Port Forwarding and NAT, these two concepts seem similar to me.
Is Port Forwarding a type of NAT?
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Site-to-Site VPN with BOTH sites behind NAT (mobile data routers)
I have 2 sites (call them "A" and "B") which connect to the Internet using 4G mobile data routers - don't knock them, I'm getting 200Mbps downlink and 30Mbps uplink, faster than a ...
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Do NAT Gateways Need to be the First Address of the Network?
NAT gateways are often given the first usable address in an address space.
Do any protocol specs require this? Or is this just a convention?
I skimmed RFC 1918 and RFC 2663 but didn't see anything ...
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How does NATing work
I'm not 100% understanding how NATing works. Let me setup our network and talk this through.
So first of all, lets say that I have an IP size of 4 bits so 16 possible combination. The only private ...
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Full Cone NAT on Cisco router in Packet Tracer
I am trying to create a network with two subnetworks with private IPs. I need to configure symmetric NAT on edge routers within the subnetwork.
Diagram:
I need to configure NAT on Router0 and Router2....
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Is it possible to send network messages with "Fake" Local Network(192.168.x.x) destination IP but actually reaches the destination via internet?
I am configuring a MySQL server that is only intended for computers from internal network/local network machines to access.
Now MySQL has a "bind IP address" setting that, if I set it to the ...
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1
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260
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Cisco ASA VPN tunnel shows up (phase 1 and 2, MM_ACTIVE), but no traffic passes
My end of the tunnel is on an ASAv in AWS. (version 9.14)
show crypto isakmp sa
4 IKE Peer: 212.239.x.y
Type : L2L Role : responder
Rekey : no State : ...
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How are we still able to use IPv4 address even with NAT? [duplicate]
My question is why haven't we run out of IPv4 public IP as well because now almost all home has a router which is assigned a public IP. Is it possible to have multiple layers of NAT on the router-ISP ...
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Why are External NAT ports different when both NATs are restricted cone? [duplicate]
I'm in the progress of implementing my own Signaling server with UDP hole punching, everything have been smooth up until both hosts were behind Restricted Cone NAT, then the ports for P2P ...
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1
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439
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Checkpoint Firewall using wrong Source IP when establishing a VPN
I have a checkpoint VSX environment running r81 and I have a DMZ firewall that has two external interfaces. One that goes to the Internet and one that goes to a 10.0.0.0/8 network that connects to ...
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3
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why ip adresses are divided into network portion and host portion when we already have NAT [duplicate]
I don't understand why ip adresses are divided into network portion and host portion? is the host portion really necessary when we already have NAT?
for example, if ip addresses only have network ...
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Trying To connect Router4 to internet
In the picture, I have a part of my topology. The concept is that I am trying to configure OSPF in my network. Internet is a nat cloud module. The routers are all iosv routers.
ISP 1 has the following ...
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Configure NAT in Vyos Router
I have the following diagram, and I want that R2 and each client connected with R2 have access to the internet. For that I configured NAT in R1 with the following commands:
#set nat source rule 10 ...
user80646
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3
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How NAT router use layer4 contents in layer3?
I followed from this question and @PeterGreen's Answer , and come to know that NAT router working in layer3, but using layer4 contents(layer4 port number,layer4 checksum). My question is when layer3 ...
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Does Port Forwarding limit ports available to NAPT?
I'm wondering if routers limit the possible ports available to NAPT when port forwarding is configured. For example, given one public IP address all but two ports assigned via port forwarding, would ...
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Switching Internet connection on Cisco ASA
I use Cisco ASA in branches of our organization. Each device has an IPsec tunnel that connects to the main office. To access the global network each device also has a NAT. Recently, a task arose to ...
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What is the use of SNAT (Static Network Address Translation)?
If SNAT is used to map internal private IP addresses directly to a non-changing public IP address, why not simply assign the public IP addresses directly to each host itself? What advantage dose SNAT ...
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595
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Why or when do we need Layer 2 NAT? [closed]
What is the point of public addresses in Layer 2? Why or when do we need it? When is it healthy to use? Or is it even a common thing?
Sorry I am kinda new at networking and I just googled it but ...
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2
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How can I use scapy to make a port appear open-device behind NAT?
This has been asked in stack overflow like 7 years back. I don't see the correct answer there. Is there any way to do this?
While this packet keeps on being transmitting, doesn't the other end see the ...
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1
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191
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NAT in ASA (5505) Firewall is not working for VLANs configured in Layer3 Switch?
Toplogy:
Tool Used: Cisco Packet Tracer
Scenario:
NAT for hosts in any of the VLANs of Layer3-Switch not working.
Ping requests reaches outside server, but NAT is not working so ISP
Router can't ...
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How to configure NAT in Cisco ASA Firewall for all VLANs connected to layer 3 switch? [closed]
Topology:
How to set up NAT in Cisco ASA Firewall (in Packet Tracer), when there are VLANs in the network?
In the current approach, NAT is not working to reach the server (8.8.8.8) from any of the ...
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Cisco 2851 Static NAT Entry - Similar Static Entry Already Exists
Thank you in advance.
I have a few 2851 Cisco ISR. This is my NAT Pool config;
ip nat pool NAT-Pool 38.xxx.xxx.193 38.xxx.xxx.206 prefix-length 28
ip nat inside source list 1 pool NAT-Pool overload
...
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1
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68
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What's the procedure to limit a subnet on a Cisco router from seeing another subnet when both are using NAT?
I have a Cisco 891F router. The internet is hooked up to G8. The student network is Vlan 200, and the Office is Vlan 100.
(I know the internet has an internal subnet (192.168.1.5), but that's because ...
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NAT not working in cisco packet tracer
Cisco Router Version: 16.7(3r)
Cisco Packet Tracer:8.0 x64
Router(config)#interface dialer 1
Router(config-if)#ip nat?
% Unrecognized command
Router(config-if)#ip nat ?
% Unrecognized command
Router(...
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1
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49
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Linux: address the same IP range (different networks) via two interfaces masqueraded [closed]
Not sure whether it can be done:
Due to a legacy setup there are two separate networks that both use the same class C subnet 192.168.0.0/24. I have a Linux box with two physical interfaces wherein ...
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Are NAT external:internal mapping types the same for UDP and TCP
Suppose I use a STUN server (UDP) to determine that a client's NAT randomly assigns external port values.
Does this imply that the client's NAT will also assign random external port values when using ...
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How to perform an inbound and outbound NAT at the same time in Pfsense?
I have a rule on a stormshield performing NAT on both the source and the destination address. It is done very simply in one rule. Example :
--Before translation-- --After ...
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3
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978
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Private IP address vs Local IP address
Say a router is connected to two devices. Now the router will give those two devices different private IP addresses. The router itself has a private IP address (which serves as the default gateway for ...
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Questions about NAT
So i just started learning about NAT and networking in general. As powerful as this technology may seem, it was specifically made for reducing the amount of IPV4 addresses used throughout the internet,...
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Cisco ASA nat from inside to outside, but network that is routed to inside interface
So is it possible to nat from inside to outside interface but not the inside ip subnet, rather the ip subnet that is routed to inside interface?
#object network remote_ip_subnet
#subnet 192.168.1.0 ...
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How does NAT modify the headers correctly?
How does the process of replacing the incoming message (say from stackexchange) to the router, and modifying the header with my PC IP happen? How does the router know which IP to insert there? Is ...
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