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Questions tagged [nat]

For questions about Network Address Translation (NAT), a method of modifying network address information in IPv4 packet headers.

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1answer
13 views

NAT from a non default gateway router [on hold]

I have a network with two different routers, like this: Router1: WAN 1.1.1.1 LAN 10.0.0.1 Router2: WAN 2.2.2.2 LAN 10.0.0.2 PC1 (Windows 7) : LAN 10.0.0.11 GW: 10.0.0.2 PC2 (Windows 10): LAN 10.0.0....
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0answers
19 views

Route traffic through SRX without destination NAT

I'm trying to allow hosts in the untrust zone to access some server resources in the trust zone. There is some port overlap between servers that is causing problems with destination NAT. What I'd like ...
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0answers
20 views

Problem in NAT Outside configuration [closed]

im learning networking in my course. i followed NAT course in this site NAT PROBLEM . i did the setup as in the diagram then setup the NAT on R2 as mentioned in the page. I didn't do routing because ...
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0answers
11 views

Personal Wifi Hotspot — Public IP of connected devices [closed]

Network SMEs, I am kinda confused with what I am seeing with my hotspot connection on my iPhone (ios ver12). Connecting laptop (windows 10) to internet via iphone hotspot. I used google to see what ...
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0answers
13 views

Can I have more than one outside object point to one inside object?

I have a NATed SFTP server that gets packets from the firewall (Cisco ASA 5505) from the public address of x.x.x.207 and I want the SFTP{ server to also get SFTP packets sent to x.x.x.209. In my ASA ...
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1answer
53 views

Accessing internal website from subnet

I have the following network: - Edge Lite 3 router with public IP on WAN (eth0) and 2 LANs: 1) eth1 192.168.1.11/24 2) eth2 192.168.2.11/24 eth1 is DHCP, I have several work laptops inside. eth2 ...
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1answer
18 views

A question on NAT [closed]

I know ISP's use NAT to provide a home user with a public IP. If multiple devices connect to the internet using the same router all will have different private IP addresses but similar public IP ...
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1answer
14 views

Daisy chaining IOT devices without switches? [closed]

I have multiple IoT board with two network interface in each device. I want to connect them in a daisy chain without help of switch. The eth1 of first device will be connected to eth0 of second device,...
4
votes
1answer
319 views

Will the data transfer with the destination on the same LAN network be routed through the internet when the WAN IP is used?

I'm planning to set up a Nextcloud locally. I will be using my own domain with a DNS record to connect to my WAN IP and port forward the needed ports to the local machine running Nextcloud. Now of ...
2
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2answers
97 views

NAT Translation Table Port Number

I had a practice question about a NAT-enabled router with outside address 24.34.112.235 and inside network 192.168.1/24 and three inside hosts .1, .2 and .3. The three hosts all open two connections ...
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3answers
60 views

Can I make 2 ISP providers' IP addresses into 1 IP address?

We have 2 ISP providers (X, Y) and we have connected the ISPs to a core switch>Sophos firewall>Switch rack>end user (LAN & WiFi). This ISP works on fail-over mechanism. The issue here is that we ...
3
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1answer
141 views

PAT not translating at all

I am studying for my CCENT. I threw together a PAT practice lab. Other than DHCP and RIP everything is pretty stock. No VLANs No security Just NAT overload on ACCESS router. I am stumped why it isn'...
4
votes
1answer
29 views

Source NAT on Juniper SRX300

I'm having issues setting up the Source NAT on my SRX300 firewall. The firewall is connected to an LC-panel through a fibre optic cable in port 0/6. I have set the public ip on that interface and have ...
3
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2answers
42 views

How could a response be sent to the requestor without requestor's address?

I'm reading this talking about the differences between two fire-and-forget message (for example, under UDP) and a request-response communication (for example, under TCP). I came across this: The ...
1
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1answer
47 views

Access internal webserver with domainname points to external IP

We have a webserver on our LAN. Externally, we can use the public domainname (let's say business.com) to access the website. Internally, we need to use the local IP. We also want to use the public ...
1
vote
1answer
45 views

How to run SIP phones in the LAN (NAT Overloaded to single IP)?

We have a small office network switch connected to a DSL modem for internet and telephony access. Now we would to extend network to another location in the same building for which I deployed a cisco ...
2
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1answer
156 views

Can VPN on router connected to the modem bypass a double NAT created by two routers unbridged and connected to each other?

I can't seem to get my head around this scenario. If I am right, a VPN configured on the client-side/workstation would definitely bypass double NAT but on this scenario: Modem <-bridged-> Router ...
2
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0answers
42 views

Cisco - Change both source and destination on NAT [closed]

Note: As usual I'm dealing with single device so there are limits on what I can change outside of this router. Device: Cisco 1841 IOS: 12.4(13a) Vlan1 - IP: 192.168.0.3 Vlan1 (Default Gateway): 192....
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1answer
160 views

NAT VLANs with same IP Subnets

I have a VMware environment in which VMs are running a simulation suite. The software used has hardcoded IP addresses, about 10-15 VMs, and we are running multiple instances of this software each in ...
55
votes
7answers
14k views

Why are IPv4 addresses running out?

I understand that we are running out (or ran out already?) of IPv4 addresses, but I don't really understand why that is. Right now, every home has its own IPv4 address (dynamically assigned, but still,...
0
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1answer
36 views

Cisco IOS 12.3 - Mysterious NAT - Where is it defined?

I have the following config (IOS 12.3): A.B.C.13 stands for the outside, public IP, bound on interface Fa0/1.52 37.247.X.206 is a public client I am using to test x.x.x.n stands for a random public ...
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1answer
33 views

Does the VM under the NAT network can contact the dedicated servers? [closed]

I have bellow snapshot's network configration: in the Dedicated Control Server(172.18.1.249) there is a VMware VM1 with ip 172.18.1.247, and it use the NAT network(gateway is 172.18.1.248). I want ...
2
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1answer
273 views

Port-forwarding rule on Cisco ASA not working - “Drop-reason: (acl-drop) Flow is denied by configured rule”

New to Cisco, so I hope this question isn't too noobish. I am trying to setup a port-forwarding rule to allow "any" SSL traffic in from "Outside" to the web server on my LAN. The problem is apparently ...
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1answer
101 views

ASDM access broken on Cisco ASA 5505 - NAT rule gone wrong

I was trying to setup NAT and Access Rules and apparently did something very wrong because now I cannot get into ASDM at all. I've tried multiple machines and all of them time out. Also the landing ...
2
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1answer
49 views

Network ( routing and switching) , security

In my company network i am installing new cisco2811 router but i have problem, my LAN network can not ping and access network. i get point to point internet from ISP. PTP IP is 192.186.86.200/24 and ...
2
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1answer
56 views

Firewall Rule 'Both Ways'

I'd like to think I have a good understanding of NAT and Firewall rules at a basic level, though please correct me if I'm wrong at any point. I've seen many products list their firewall requirements ...
1
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1answer
88 views

Is an SBC sufficient and can it NAT

We have a gateway which faces out to our VoIP SP. As we get more users we need some security in front of it. Currently our gateway terminates directly to the SP. We would like to put a SBC in front ...
4
votes
6answers
609 views

Why is classful addressing considered waste?

I am trying to understand the addressing strategies. But there is something which I can't grasp. Maybe I am missing a very basic point, if so, I am sorry beforehand. From my researches, let's say, if ...
1
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0answers
119 views

pfsense Server Load-balancing on LAN Interface [closed]

I am trying to load balance a couple of web servers from the LAN side as I don't need access from the WAN so that clients on the LAN can access these web servers: LAN IP is 192.168.10.1 I created a ...
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2answers
334 views

How does NAT work with incoming UDP packets from unknown IP

Apologies in advance for the relatively noob question and if this is off topic here ( I am not sure...) The situation is that I have a UDP client and server bound to the same port. My understanding ...
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1answer
48 views

Outbound NAT for single host behind an ASA located over an IPSEC tunnel [closed]

I have these two nets connected over the public internet with ASA 5510s. 192.168.0.0 < -- ASA1 ---> Internet <--- ASA2 --> 192.168.5.0 Each net does either a simple dynamic or static nat ...
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0answers
169 views

what is a reverse nat and why would i need it? [duplicate]

Though I could find some definitions of reverse NAT (like from here), I couldn't really understand why it is needed. I'd really appreciate some examples. And please don't get confused with the "...
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2answers
129 views

Leak default route to multiple VRFs while keeping VRFs isolated from each other

I'm working on a configuring stuff on a Cisco Nexus 3k based platform and trying to isolate different things into different VRFs which should not be able to talk to each other. Some of these VRFs ...
1
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1answer
30 views

Connect office to multiple customer VPNs

First time post here so if this is off topic please let me know where to ask this question. A company that provides outsource billing services to multiple client companies using VPNs to each remote ...
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2answers
95 views

Why does NAT keep track of each packet not just connections?

I have tried packet tracer and actual cisco routers and I find this weird: NAT uses different source ports, usually incrementally, for consecutive packets from the same connection. Why is that? ...
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2answers
62 views

How does the NAT work [closed]

I have a public ip assigned by isp, two phones are connect to wifi router. In both the phones i am seeing news feed on different facebook accounts, so facebook gets packets from only one publuc ip ...
2
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3answers
120 views

Why can't a host B act as a server, and accept TCP connections, when sitting behind a NAT?

Originally, I thought I intuitively understood why B can't accept TCP connections, however when I read about how P2P applications circumvent this exact problem by using an intermediate peer that is ...
2
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2answers
803 views

Why to use public IP addresses within private networks?

I have started to work in a multinational company which has a global network spanning across 4 continents (20 0000+ network devices). I noticed that a lot of end user devices (PCs, laptops) have IP ...
2
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2answers
116 views

What is the point of outside NAT?

I understand how outside NAT works, but I do not know when it should be implemented? Could you please tell me some scenarios when outside NAT is needed? Thanks!
8
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2answers
725 views

routing between vlans not working

I need to put a Cisco router behind an ISP router. (The ISP doesn't allow us to use their modem only.) I've called the ISP technical service and they've set up the connection with me. Their router ...
2
votes
1answer
440 views

Configuring the NAT 1:1 rules with pfsense

I have two pfsense. One pfsense is on 192.168.0.1 and another pfsense is on 192.168.20.1. Basically I have installed 20.1 pfsense on one machine 192.168.0.180 which is in the network of 0.1 pfsense, ...
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1answer
28 views

Why specify additional NAT rule

In watchguard's guide for NAT loopback when describing the additional nat rules required, they show this image: Why are those top two NAT rules necessary, ie aren't they already covered by the next ...
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2answers
57 views

IPSec - NAT-T inner/outer IP of the gateway?

I was configuring an IPSec VPN and somehow I can't figure out what the inner/outer IP of my gateway would be. Have a look at this image : Imagine I have my site-to-site VPN, with my gateway having ...
0
votes
1answer
32 views

Discovering public ip from wifi signals, shodan, parent router NAT [closed]

MAC addresses innately do not change right? and you're able to scan for broadcasting APs where you'll be able to detect different nearby mac addresses of each AP.. Public IP addresses change, ...
2
votes
1answer
61 views

Asa5508 NAT two internal IPs

Hello I have a Cisco asa5508 and I want to NAT 2 internal IP's to 2 public IP's that I have.Each IP on its own. Currently I have NatPool and it's working either with the one IP or with the other. Is ...
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1answer
84 views

Is NATing possible in case of IPV6 addressing mode anyway?

Setup: A(2001::1:123) <------> B(2001::1:124) <------> C(2001::1:125) where A,B and C are the systems.And apply rule of NAT(SNAT/DNAT) on system B for forwarding a packets from C to B,B to C,A ...
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4answers
2k views

What is the difference between DHCP and NAT?

Both seem the same to me. I don't see how DHCP is different from Dynamic NAT. Can anyone please help?
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1answer
68 views

2 Wan DHCP to cisco router

I have a cisco 2921 router and 2 wan ips provide by 2 diferents isp via dhcp. The main connection is funtional right now, I have a subnet with a nat to this ip, but I want put the second ip just to ...
1
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1answer
272 views

ASA VPN Tunnel NAT Issues

I've been trying to jump through two tunnel. A Customer has a cloud solution which we need access to. Since we already have a vpn site2site tunnel to the customer we can already access his LAN. What ...
2
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2answers
83 views

How does/did an ISP serve so many people over IPv4

Whilst reading Tanenbaum - Computer Networks they talk about IP scarcity at the level of ISPs: IP addresses are scarce. An ISP might have a /16 address, giving it 65,534 usable host numbers. If it ...