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Questions tagged [port-forwarding]

For questions about port forwarding on an on topic network device. For instance, you have a firewall and need to forward a port to an internal server, but you do not know how.

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How to change the source port without interrupt the TCP connection? [closed]

I use TCP socket to connect a client(source) and a server(destination), the connection has been established. Now the project need to change the source port without interrupt the connection. Both ...
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1 vote
0 answers
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How do I port forward multiple SSH servers? [closed]

I am very new to networking and I have set up ssh on my raspberry pi. I also have ssh on my windows 10 computer. Here is my problem: I would like to have ssh port forwarding on both my raspberry pi ...
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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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Can a router port forward based on a request header? (noob question) [closed]

I'm searching for a router that supports port forwarding based on the request header. e.g. www.domain1.com should forward to port 80 on IP 168.0.1.10 www.domain2.com should forward to port 80 on IP ...
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-1 votes
1 answer
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How can someone connect to my computer even through port forwarding?

If I set port forwarding up on my router to redirect connections on port, say, 50000 to my computer, how can someone connect to my router in the first place ? Does that mean that my router has a ...
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1 vote
2 answers
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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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0 votes
1 answer
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Hosting a website using dynamic public IP: What if the ISP did not assign any port forwarding? [closed]

Let's just say that I am a peasant that can only avail of a typical Dynamic Public IP address from my ISP. Just for the sake of example, let's say have the following: Domain Name: experiment626....
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1 vote
0 answers
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WAN ip address looks like private ip, but whatsmyip shows a public ip address [closed]

Let me preface this by saying that I'm not very good with internet networking, but I tried my best to gather information. So I've been meaning to do some port forwarding to open a server, but I got ...
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1 answer
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Cisco 887 Conditional Port Forwarding

I have port forwarding configured on a CISCO 887 for client VPN like this: "ip nat inside source static udp 10.65.1.1 500 interface Loopback1 500" It forwards them to a VPN server. However, ...
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1 answer
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What IP addresses are appropriate for a network inside an embedded device? [closed]

I am making an embedded device with two processors, a "gateway" processor which is connected to external ethernet, and a "webServer" processor, which is only connected to the ...
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0 votes
1 answer
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Port Forwarding using specific VLAN on CIsco RV134W

I would like to forward internet traffic on a specific port to VLAN30 on our network for our security cameras. I have a Cisco RV134W VDSL gateway connected to a D-LINK DGS-1210-28 switch. The port on ...
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2 votes
2 answers
269 views

Difference between "Destination NAT" and "Port Forwarding"

As far as I can tell "Destination NAT (with PAT)" and "Port Forwarding" are different terms for the same thing, or are there any technical differences? Note: I added PAT because ...
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Are computer ports part of the network level of part of the operating system level? [duplicate]

I know that computer systems can communicate one with the other via ports, say from port 80 of computer system X to port 80 of computer system Y. Are computer ports part of the network (hardware) ...
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Can port mirroring be used to convert single video stream to multiple video streams?

I am new in networking and had a basic query regarding port-mirroring. A video stream is taken from camera-based software system and is being fed to a distribution system. For high availability (...
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0 votes
1 answer
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Easiest setup to replace jumpbox forwarding [closed]

In order to connect to some of machines, what I currently do is: Connect to VPN (using AnyConnect) SSH to my jumpbox via VPN For every single machine that I want to access using ssh, I have to map ...
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1 vote
3 answers
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Difference between Reverse Proxy and Port Forwarding

Well both reverse proxy and port forwarding looks for any incoming packets destined to a particular machine which is present in local network. How both of them are different ?
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0 votes
2 answers
316 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 ...
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How do programs ensure the port they are listening to is not already in use? [closed]

I'm just curious about this, but I know there is a range of ports that programs can use, but I'm curious how do they know that the port they are listening to isn't already in use by another program? ...
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0 votes
1 answer
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Why is the IPv6 address I'm getting from whatismyipaddress.com wrong? [duplicate]

So I've portforwarded my machine using the graphical interface provided by my router. This interface also gives me a public IPv6 which I can use to communicate with my machine through the internet. ...
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0 votes
1 answer
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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 ...
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How to forward port 80 and 443 on pfSense to a (internal) nginx webserver?

Yesterday we did a "big bang" firewall switch in our company. Our new firewall is a pfSense server. Lets say our external ip is 84.1.1.1, pfSense is 192.168.1.1 and our web server ip is 192.168.1.2. ...
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When port-forwarding, will a port only be listed as OPEN if the service host is actually reachable?

I'm fiddling around in my lab today and attempting to learn more about port-forwarding. I've noticed that when I set up port-forwarding for a given port and run a port scan from outside the network, ...
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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 ...
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0 votes
2 answers
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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 ...
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1 vote
1 answer
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Port Forwarding on Cisco ASA 5510

I have an EDI server behind a Cisco ASA 5510 version 8.2(1). Currently our EDI server sends over documents to our trading partners and they will look for our URL in this format http://1.1.1.1:1000. ...
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1 vote
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Port forward no destination [closed]

Context: I'm running a home game server and my paranoid network administrator has allowed port forwarding under the sole condition that I airgap the server hardware when I'm not actively using it. Our ...
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0 votes
2 answers
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Why can some people use public ip address to access a server from an internal network with the client device within the internal network [duplicate]

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 ...
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1 answer
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How can I configure a Cisco router 4300 to allow internal server ip:80 to be accessed on public ip:4500

I have an internal web server on port 80. I need help commands maybe to configure port forwarding to access the server on my private network from a public IP Current running config interface ...
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0 votes
1 answer
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Problem Forwarding Port 22 for SSH [closed]

I'm trying to forward port 22 so I can SSH into my PC from a different network but it doesn't seem to be working. I can do ssh mihkel@my_public_ip from the network that the PC is on but it doesn't ...
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2 answers
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If you're behind a firewall and all the ports are blocked, how is your browser able to access the internet? [closed]

I'm behind a router and I'm able to run game servers on my home computer after forwarding ports or using the DMZ feature on the router. However, I still don't understand the underlying technology as ...
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0 votes
2 answers
2k views

How to connect multiple devices with identical static IP into a wireless network

I've been searching StackExchange and the Internet for a while looking for a solution for my networking question. Some articles I found are here, here and here, but these don't need to deal with a ...
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1 answer
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RDP on IPV6 using DS-Lite-Tunnel [closed]

I am trying to access one of my PCs from and external network using RDP on port 3389. After realizing my ISP uses DS-Lite-Tunnel I gave up ipv4 and focusing on ipv6. So far the only way I managed ...
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0 votes
0 answers
337 views

Simultaneous dynamic and static NAT not working

Cisco 4200 series running IOS XE with a single public IP address and dynamic NAT, which works just fine. I am trying to add Static NAT to access a server (map external port XX to internal port YY. ...
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5 votes
1 answer
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Cannot get port-forward working on ASA 5505: "Drop-reason: (acl-drop) Flow is denied by configured rule"

Months ago I made this post here on NE, but I still for the life of me just cannot figure our port-forwarding on my ASA 5505. I have since started over and am now trying the DMZ port instead, but ...
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3 votes
1 answer
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In port forwarding, is the ultimate destination decided solely by the intermediary entity?

In port forwarding, is the ultimate destination to connect to solely decided by the intermediary entity which provides port forwarding, not by an application client? Although the page mentions dynamic ...
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3 votes
2 answers
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Why isn't web traffic blocked by router?

(A naive/stupid question which I couldn't find answer to on the web.) Why is the internet traffic reaching me even if I haven't set up port forwarding. (For example, I can view websites). What I ...
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0 votes
1 answer
1k views

Port Forward for OpenVPN Server behind two routers [closed]

I am stuck how to establish port forwarding between the Internet and an OpenVPN server behind two routers. I need the first router as an Internet DSL modem and VoIP phone access (both services from ...
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1 vote
1 answer
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Reach IP in Parent Network [closed]

We have a router (Router 2) inside a network (Router 1) with a client (Client in Router 2) that needs to make a TCP connection to a client in router 1. We only have access to configure Router 2 and ...
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2 votes
1 answer
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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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1 vote
2 answers
915 views

Configuring static NAT on Cisco Router

I am trying to configure port forwarding on a Cisco 891F router given by an ISP and directly connected to servers in the 192.168.170.0/24 network. The ISP recommended using the ip nat inside source ...
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1 answer
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Port forwarding using Putty [closed]

I have a server (running ubuntu) where I am running BRAT(http://brat.nlplab.org), which creates a standalone server at http://127.0.0.1:8001. Now I want to access this in my local machine (Windows 10)....
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1 vote
2 answers
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Can ISP know whether port forwarding is been done? [closed]

I sit behind a NAT of an institute, which has a rule that implies that no port forwarding can be done. I am developing a peer to peer application, which I need to test. So I have to be sure that it ...
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1 vote
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SSH into device attached to another router [closed]

I saw this questionwhich looks kind of related, but I'm not sure as the answers are too confusing. Basically, I want to SSH into my Raspberry Pi from my laptop. Eventually I want to have the Pi ...
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0 votes
2 answers
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Simplest explanation of ports, sockets, processes [closed]

Can anyone explain the simplest definition of what ports, sockets and processes are and what is the relationship between all 3. Thanks in advance.
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5 votes
1 answer
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Switch FIB and router FIB

Forwarding Information Base (FIB) also called Forwarding Table or Mac Table according to wikipedia. I first explain my understanding of the FIB in both Switch and Router. Does not hesitate to correct ...
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1 answer
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SSH and port forwardings in both directions [closed]

I can't undersatand this : All communication happens using SSH with port forwardings in both directions Any help? Thanks.
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1 vote
1 answer
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What requirements must general firewall/routing software meet, to make OSI 2 port mirroring work correctly?

The basics are obvious, but there are technical points of networking implication which I don't understand. Some of these are general to networking, others general to all routing/firewall softwares ...
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1 vote
1 answer
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Help understanding "tunneling"

Tunneling = allows a network user to access or provide a network service that the underlying network does not support or provide directly (wikipedia) How does the "network service" not support a ...
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1 vote
1 answer
324 views

Cisco Router, Port Forwarding, ACL ordering

I'm new CCNA learner here. If I have the following access list: access-list 101 permit ip 10.10.0.0 0.0.255.255 any access-list 101 deny tcp host 10.10.0.1 eq 443 any access-list 101 deny tcp host ...
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2 votes
1 answer
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How to setup port forwarding on Cisco Router running Version 15.2(4)M6

I'm trying to get traffic forwarded from my network's public IP to a private IP within the network to allow access to a server from outside the LAN. I can't quite figure out how to do it unfortunately....
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