5
votes
Accepted
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 ...
- 30.8k
4
votes
Accepted
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 ...
- 461
3
votes
Accepted
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 ...
- 1,156
3
votes
Accepted
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 ...
- 9,108
3
votes
Accepted
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 ...
- 56
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
- 121
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 ...
- 9,305
2
votes
Accepted
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/...
- 3,982
2
votes
Accepted
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 ...
- 259
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....
- 3,228
2
votes
Accepted
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
Accepted
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 ...
- 202
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 ...
- 9,108
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 ...
- 9,108
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 ...
- 73.4k
1
vote
Accepted
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
Accepted
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-...
- 136
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 -...
- 21
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 ...
- 1,156
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 ...
- 136
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 ...
- 11
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 ...
- 63
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
Only top scored, non community-wiki answers of a minimum length are eligible