Questions tagged as ['router']

A device that connects two or more networks and is capable of forwarding data packets to a destination based on information contained within a packet and internal routing tables.
Score: 1
Sheik avatar
How can I MASQUERADE between vlan bridges
us flag

I have created two VLAN bridges in openwrt based system which has single physical interface.

*) eth0->lan->br-lan
*) br-lan->br-lan.2(VLAN INTF)->br-vlan2(BRIDGE INTF)
*) br-lan->br-lan.20(VLAN INTF)->br-vlan20(BRIDGE INTF)

I am running an DHCP server in by ubuntu machine.

I am trying to route between the vlan to open up the intervlan communication. But i couldn't succeed.

what i ...

Score: 0
Is it OK, to use iptables SNAT rule with inverted -o parameter?
cn flag

Would it be OK/reliable, to use just one rule?:

iptables -t nat -I POSTROUTING ! -o eth2 -s -j SNAT --to PUBLIC_IP_ADDRESS

The BGP linux router has 25 ethernet interfaces. This iptables rule with "! -o XY" should allow the traffic to be SNATed and leave the router through all interfaces other than eth2. Behind eth2 interface, there is a local network - those machine ...

Score: 0
Said Jawad avatar
Netflow records with Destination Ports 1025,257 and Protocol as ipv6-icmp
ng flag

I have some Netflow records from a bunch of routers. The records contain IPv6 flows and there are entries with protocol as ipv6-icmp and their destination port values as 0, 1025 and 257. I know from this link that the value of 0 for ipv6-icmp in netflow indicates an echo reply. Is there any resource to find the meaning of the ipv6-icmp-1025 and ipv6-icmp-257?

Score: 0
Scheintod avatar
ipv6 distribute an ula prefix without an router
bz flag

I have a network which has no ipv6 connectivity to the internet. But I'd like to play a little with private networking.

So I want to use ULAs for my devices and automatically distribute the prefix.

I know that ipv6 uses router advertisement to do so. But (hence the name...) it advertises a router, too. In my case using dnsmasq it's the address of the server running it. So it ends up in my clients as ...

Score: 0
Router forces browser to use older, presumably cached, webfiles
cn flag

We are trouble shooting website where we deploy a new version but our Computer browser still pulls the older pages. When we disconnect from the router (WiFi) and connect to a hotspot (mobile phone/data), the browser correctly pulls the new pages. If we switch back to the router (WiFi), the problem returns. We have tried trouble shooting

  • We have confirmed the new files were successfully deployed
  •  ...
Score: 0
Leon avatar
Should I do the stateful matching with iptables for nat table?
gd flag

I often see that there are some stateful matching rules in a iptables' chain such as INPUT.

I known what they are doing, and I'm interested in that

Should I do the same for the chains of the table NAT?

For example, in my home router, I want it accepts ssh, and also acts as a NAT router.

If we have:


-A INPUT -p tcp -m state --state NEW -m tc ...

Score: 0
iptables: How to block UDP between devices on LAN-side of gateway (using dd-wrt firmware)
cn flag

Goal: To block UDP traffic to devices on LAN-side of this gateway (using dd-wrt firmware), that communicate with internet and each other, to test specific communications applications running on each device.

Exceptions: allow the bare minimum UDP needed to support basic network operations for these devices to continue communicating (eg: via TCP) with internet and each other.

What I've tried so far

Score: 0
How does "DROP all anywhere" in the FORWARD table not render my router useless?
cn flag

I recently learned about IPTables and IP routing in order to configure a single-board computer to isolate a particular machine from the rest of my network, while still permitting it to access the internet, among a few other rules.

I decided to use this new knowledge to enhance the security of my embedded media devices (and maybe prevent them from displaying ads and reporting telemetry). I had an ...

Score: 0
Looking for the best recommendation to join two different LAN networks running on two different routers
ph flag

First, I'll try to explain the current network layout. I'm not a super-experienced networking professional (yet...) and I have come up with a possible solution, but I wanted to run it by some experts and see what the cons are to my plan.

So we have a small business setup servicing about 12 users, right now it looks roughly like this:

Comcast Business Modem (providing two public IPs), this modem i ...

Score: 0
How to add the normal routing information of a router to BIRD?
us flag

Suppose the following network layout:

                         R1:                                   R2: <---, <---------->, ---> 

BIRD is installed on both R1 and R2. All information about the network topology is automatically given. It was my understanding that BIRD would automatically redistribute this information so that ...

Score: 1
iptables - how does one use multiple prerouting sources to force dns traffic through a particular IP?
br flag

I know this question has been asked historically, but the answers I have yet to find are not all too helpful in this one niche use case.

I currently have one router running DD-WRT on, one router connected to the previous with IP that runs as a VPN client, and one Raspberry Pi set up to run DNS filtering on

Ultimately, my goal here is just to  ...

Score: 0
Routing issue while using 2 router Draytek Vigor 3910 with VLANs
it flag

I'm having problem when using 2 Draytek Vigor 3910 at the same time. This diagram was working well with Vigor 3900 but they replaced to new model 3910.

enter image description here

My issue: 1, OSPF between 2 router's not working OSPF config:

  • LAN1, vlan51,52,53 was enabled on Router 1, area 11, id 1, same password, md5 disabled
  • LAN2, vlan54,55,56 was enabled on Router 2, area 11, id 1, same password, md5 disabled Both Routers can  ...
Score: 0
Does traceroute use the same path?
cn flag

I was a little bit confused about the use of traceroute.

According to this

The traceroute command is used to see how packets are getting routed. It works by sending packets with increasing TTL values, starting with 1. So the first router gets the packet, and it decrements the TTL value by one, thus dropping the packet. The router sends back an ICMP Time Exceeded message back to us. And then the n ...

Score: 0
Jacob Waters avatar
How to port forward on an ATT Router/Modem?
cn flag

I am trying to open port 2222 for an open-ssh server on my linux machine.

I am able to log into it just fine from my local IP address.

sudo systemctl status returns:

     Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled)
     Active: active (running) since Sun 2021-10-10 19:25:19 PDT; 34min ago
       Docs: man:sshd(8)
    Process: 9445 E ...
Score: -1
Ensuring internet is disabled for devices connected to second router
es flag

I think I have two routers:

Router A is connected to WAN and the Router A DHCP gives out IPs in range to

Router B is connected by ethernet cable to router A and gives out IPs in range to

The aim is that devices connected to Router B WiFi cannot connect to the internet - so, Router A has a rule applied that disables the internet for IPs 192.168.0. ...

Score: 0
RRAS NAT on specific fixed IP address
ng flag

I have an AWS EC2 VPC-based Windows Server instance that has two private IP addresses and two elastic IP addresses on a single network interface with IP addresses:

IP Role Primary Secondary

I have configured in the NIC the primary IP address and under the advanced tab I have added the secondary IP address however this has caused an undesired effect under R ...

Score: 0
port forward only for vpn clients on draytek vpn router
ru flag

I have a VPN server set up on a vigor 2865. I now want to allow one external ip address, or anyone connected to this vpn, access to a website on an internal server. This website uses a public dns name to resolve to my public ip address. e.g.

If I port forward 80/443 to the internal server then anyone can access the site. This works fine.

If I add a firewall rule to only allow ac ...

Score: 0
turbos avatar
Reached cloud router limits
us flag

I have reached the limit of 5 cloud routers per region, if I edit the quotas I can see only a project limit, is it possible to increase the limit of 5 cloud routers per region? if yes, how?

Also I noticed that I can create another cloud router in a different region, if I use a different region where the resources are located which are the considerations to do (connectivity, latency, costs)

To optimi ...

Score: 0
Francabicon avatar
How do i translate the same configuration from this TPLINK router config to OPNsense
in flag

So I'm trying to connect to PPPOE but they had this config to do which i don't know how to translate to OPNsense The initial configuration:(click on the link to see it)

This is my current config (click on the link to see it) ...

Score: -1
Bob avatar
find the ip address on Linksys
gb flag

I get two differents Linksys routers : WAG54GX2 and WAP54G.

I tried to get the IP address to reset the routers correctly and verify if they are still working. So I use the RJ45 cable on my routers and linked them to my computer.

Then, I tried the default address :, I get nothing...

So I tried the cmd ipconfig/all, I get :

Configuration IP de Windows

   Nom de l’hôte . . . . . . . . . . : ...
Score: 1
Sachith Muhandiram avatar
Transient hostname was changed in a server
kr flag

In one of our production server automatically set transient hostname.
hostnamectl status shows

   Static hostname:
Transient hostname: I
         Icon name: computer-vm
           Chassis: vm
        Machine ID: xxxxxx
           Boot ID: xxxxxx
    Virtualization: microsoft
  Operating System: CentOS Linux 7 (Core)
       CPE OS Name: cpe:/o:centos:centos:7
            Kernel: L ...
Score: 0
Francabicon avatar
How can i connect OPNsense router to Mikrotik Switch
in flag

I've encountered this situation where I'm to access the switch from my router: Here is what i have set:

  • Lan (DHCP , DHCPIPV6)
  • Mikrotik (DHCP,DHCPIPV6) [connected to Mikrotik network switch]
  • VLAN_Mikrotik (DHCP, DHCPIPV6)

click on this image to see it

When i type (Mikrotik Default IP) i cannot access it. Because this  ...

Score: 1
Hash avatar
Turn Ubuntu Machine with One two Network cards into a Router
cn flag

I have a Ubuntu 20.04.2 laptop that i intend to turn into a router. I have two network cards one is wireless (wl01) which is connected to Internet. I have an ethernet card (enp3s0) IP ADDRESS to which i want to connect an Access Point that can provide connectivity to other clients.

The output of /proc/sys/net/ipv4/ip_forward is 1 I then proceeded with the following commands.

 iptables -t nat  ...
Score: 11
S.B avatar
What happens if two local systems download the same resource on same port?
cn flag

I'm aware of NAT table. I just want to know what happens if two clients in a private local area network want to download exactly the same resource on the same port? In other words , When a packet comes from the server, how can the router decide which client is supposed to get this packet?

If I'm not wrong, the incoming packet from the server has destination IP address of the router which is publi ...

Score: 0
ISP configured Dynamic IP is different from what websites see when I access them
cn flag

We switched our internet connection and now something wired is going on.

I am using a TP Link Archer 1600 modem.

The ISP asked me to set connection type as "Dynamic IP" under EWAN settings. Internet is working just fine.

But my modem shows the below IP is assigned by the ISP:

enter image description here

But when I use the external website to find my public IP I get a different one:

enter image description here

My router is configured to update no-ip. ...

Score: 0
OttoEisen avatar
Debian: no traceroute output for single host
br flag

After a recent upgrade to Debian 11 on my router I noticed that my desktop (current W10) only sporadically gets replies when doing a traceroute across the router, usually just * * *, rarely a single reply. Several other systems (Linux/Windows) work fine, so does everything else. Using tcpdump on the router I see the incoming ICMP messages but no replies from the router. Comparing a dump from my desktop  ...

Score: 0
user3595231 avatar
How to create a compatible cisco router in EC2 case?
in flag

This is the picture of my GNS3 project, which includes Cisco Router, Ethernet Switch, and a list of my client VMs. enter image description here

If this project was created on my physical server, these are the settings I will add on Cisco Router level so that it could handle the upstream and downstream traffic.

conf ter
ip dhcp pool LANPOOL

interface fastEthernet 0/0
ip address <OUTER IP ADDRESS> 255.255.255. ...
Score: -2
trapp avatar
How to configure two addresses to access other frontends/port
cn flag

How do I configure two addresses to access other frontends / different ports, for example:

Address Mapping to (nodejs) localhost:3000 (django) localhost:7000
Score: -1
tomi7654 avatar
What is default IPv6 configuration on routers
bl flag

I've just started learning IPv6. I have a router running OpenWrt and I would like to configure it to use IPv6. As I know this address can be assigning to a client with or without DHCPv6 server. Do you know what is the default configuration on popular routers? Which method is used? Statefull, stateless or statefull + stateless?

Score: 1
VBalestero avatar
Linux router used to redirect traffic from the outside to an internal device, but the internal device needs to respond using another port
in flag

I am working on a router between an external radio/modem and my device, where the router makes a dial-up connection using the ppp protocol to the radio and sets an iptables rules between the received radio IP and my device's IP.

I have the following routes:

Destination     Gateway            Genmask         Flags Metric Ref    Use Iface
default         192.168.1000.101         UG    0      0 ...