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5 votes
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How to route a traffic from an IP/host on a certain to another host/IP on the same port

Server migrations are when you discover what name people really are using for the server. Create in DNS a service name for this, say examplething.example.com Which is not a specific host, but the ...
4 votes
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How is CGNAT routed on the client?

It uses a filter driver that picks up packets from the networking stack and redirects it. Thus there's no virtual NIC for zScaler connectivity. With the filter driver option, the app does not create ...
  • 5,168
4 votes

Block IPs without receiving traffic

There's nothing you can do. You don't control the upstream infrastructure, so you can't drop packets before they reach you.
  • 5,168
3 votes

How to route a traffic from an IP/host on a certain to another host/IP on the same port

Since both hosts are in the same network, the IP address of the old host can be assigned to the new host as a secondary IP. Then, an internal redirection can be configured to redirect traffic sent to ...
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3 votes
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Redsocks not working with Wireguard, but works with OpenVPN

Using AllowedIPs = 0.0.0.0/0 with wg-quick on Linux triggers a special case that adds special policy routing and firewall rules. These rules are designed to force all non-LAN† traffic through the ...
3 votes
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My network suddenly completely stopped working on my Debian 11 server

It is wrong to assign an IP address to a bridge member, by any method, be it DHCP or static address or anything else. If it has been working before that was just by accident, probably the NIC ...
3 votes
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How can I connect two routers to the same switch

For clarity, let's assign Router A's inside interface 172.5.1.1 and give Router B 172.5.1.254. Assuming SWITCH is strictly a layer 2 device, computers on 172.5.1.0/24 should have a default gateway to ...
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2 votes

OpenWRT - How to redirect all subdomains of a hostname, to the same host, so that it can be reverse proxied?

As of today*, this is available in Luci: under Network -> DHCP and DNS -> General, field Addresses *Merged in Sep 2020
2 votes

Why does setting MTU 1452 solve Internet problems and how to fix root cause?

TCP/IP stacks often tend to use DF ("don't fragment") bit to figure out path's MTU so that fragmentation (rather inefficient) can be avoided at all. ICMP is becoming crucial there as the ...
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2 votes
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Do routers need to have assigne IP from given VLAN to foward VLAN packages?

Routers need an IP address in every connected network they have to route from/to. Switches, whether smart or not, only need an IP address for management, none in the networks they forward packets from/...
2 votes
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In Linux how to add a route to a prefix via a specific device with certain destinations in that prefix going via default route?

As it turns out, in Linux one can use ipset matching to select routing tables. The extra ingredient is using a netfilter rule that will match the outgoing packets and apply a fwmark to them, which ...
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2 votes

In Linux how to add a route to a prefix via a specific device with certain destinations in that prefix going via default route?

Routes are calculated on a most-specific-first approach. So if your small subnet needs the default route, put that first and then add the others: Default Gateway in this example is 10.0.0.1 VPN is 10....
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2 votes
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Is ingress filtering described in RFC2827 implemented in most routers? How does such implementation look like?

Is such filtering implemented in every router that firmware such as openWRT supports? Not every router supports ACLs. Many do, and to filter by source address a simple ACL is enough. You don't have ...
  • 5,168
2 votes
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How to handle multiple public IP address with a router

First of all, I have never seen your router so I cannot tell you if it can handle it. Only someone who has the same device can tell you definitely. I would recommend trying to play with these settings ...
2 votes

How to route a traffic from an IP/host on a certain to another host/IP on the same port

All methods described below are applicable even if servers are placed far away. However, if they're close, like that in the same subnet, there are better ways to do the thing. Simple DNAT wouldn't ...
2 votes

How is it possible for a host-only VM to have internet through a host only network adapter?

Normally to understand things we split networking to the layers (in the OSI meaning) and abstract away from the unrelated details belonging to other layers. In layer 1 (physical), we have a host which ...
2 votes

Iptables route localhost:3306 to remoteip:3306

Please be aware that with MySQL on Linux localhost is special: On Unix, MySQL programs treat the host name localhost specially, in a way that is likely different from what you expect compared to ...
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1 vote
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AWS VPC Peering vs PrivateLink for network access to 3rd party cloud database

This is pretty much exactly what PrivateLink was made for. They effectively put a network interface in your VPC, you access it. On their side it hits an NLB then goes to their database. This is least ...
  • 31k
1 vote
Accepted

Why does my OpenVPN not route the network behind?

In order for your clients on the VPN network be able to reach your printers, the following are needed: A route advertisement for the clients (that you already have) A proper route on the OpenVPN ...
  • 6,945
1 vote
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Connect to device in wan network from nested subnetwork with two AVM Fritz!Box routers

Did you considered setting up a port-fowarding mechanism on router B? lets consider that device C has a WEB server listening on port 8080, needed to be reached by device D. You may configure a port-...
1 vote

Can't reach networks behind Wireguard VPN server. Split-tunneligt config on client

Solution was quiet simple. There is no need of any scripts to get split-tunneling. 1. Add this lines in wg0.conf: PostUp = iptables -A FORWARD -i wg0 -j ACCEPT; iptables -t nat -A POSTROUTING -o eth0 -...
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1 vote
Accepted

Redirecting traffic via Wireguard VPN

Sounds like you just want to be able to connect from your Network Device to your Example Client, and vice versa? If so, then this is the classic Hub and Spoke WireGuard scenario, with the VPS as the ...
1 vote
Accepted

IPv6 routing on Linux

According to this previous question, you need to set net.ipv6.conf.all.forwarding = 1 rather than (or in addition to) setting the flag on individual interfaces, which is used for controlling router ...
1 vote
Accepted

Routing between two network cards

The solution is right there: -P FORWARD DROP In your iptables-legacy ruleset, the default policy for forwarding pakets is set to DROP, and there is no rule in that ruleset which allows forwarding ...
  • 2,069
1 vote

No route to host, strange behavior

With basic installation and settings, this can only happen because there is a firewall on the VM. (there could be other causes, but not without customization that would be done by the administrator). ...
  • 9,496
1 vote

Access to the subnet of the OpenVPN server from the client side

So your OpenVPN clients (10.8.0.0/24) has valid route to 172.26.0.0/20. You can add the route locally on the client, or on the router that acts as default gateway. Note that some routers will send a ...
  • 5,168
1 vote

L2TP VPN with 2 network interfaces

##Install ipsec-vpn by script normally## ##Environment## eth0: 111.222.333.91/29 gw 111.222.333.92 eth1: 192.168.0.1/24 gw 192.168.0.254 (default gateway) ##Solution## // redirect input iptables -t ...
1 vote

route traffic through IPIP tunnels

Cracked it. Host B sysctl net.ipv4.ip_forward=1 sysctl net.ipv4.conf.all.rp_filter=0 sysctl net.ipv4.conf.tunnel0.forwarding=1 ip tunnel add tunnel0 mode ipip remote 3.3.3.3 local 2.2.2.2 ip addr add ...
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1 vote

Home Lab Routing Not Working

Configure static routes on your client to reach them. Or configure your router at 192.168.2.1 to forward packages to your other router. Note that in many cases 192.168.2.1 will send a ICMP redirect to ...
  • 5,168
1 vote
Accepted

Route traffic through physical interface

It would be very difficult (but not impossible) to have a Linux system, using a single routing stack, perform multi-homed routing of packets from itself to itself without using the lo interface. But ...
  • 9,496

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