This often happens if you are adding a secondary route, especially with Linux source based routing.
ip route add default via 10.10.10.254 table 10
RTNETLINK answers: Network is unreachable
If that happens you will probably find that it is unreachable because your NIC does not have an IP in the 10.10.10.0/24 range so just assign an IP in that range to your NIC and try again.
eg. ifconfig eth0 10.10.10.254 netmask 255.255.255.0 up........
Having a network bridge allows you to bridge traffic under multiple devices so they can talk natively without using any special routing, iptables/firewall or other trickery.
To create your bridge you need the bridge-utils package for brctl and if you want to do things like bridge VMs that run on a tap device you will need the uml-utilities which provides "tunctl".
Install the utilities to make our bridge
sudo apt-get install........
Whether you are at work, at the coffee shop or on the public internet here are some basic but effective rules for iptables that lock things down (eg. no one can SMB or SSH to you or really anything):
# Generated by iptables-save v1.4.21 on Fri Dec 14 14:00:08 2018
:PREROUTING ACCEPT [160:19844]
:INPUT ACCEPT [4:357]
:OUTPUT ACCEPT [2955:182236]
:POSTROUTING ACCEPT [2955:182236]
# Completed on Fri Dec 14........
Cisco's CUCM (Cisco Unified Communication Manager) is a system that combines voice, video, data and mobile products into a single unified management suite. At its core, the CUCMis like a "Super PBX" that controls the flow of all communications through an organization even single or multiple site deployments.
Cisco's CUCMmakes communication more effective and simple through centralized management and unification of communications resources.........
Sometimes if you have a very basic configuration OpenVPN on the client side for some reason sends all traffic to the OpenVPN server IP through the tun0 which is of course impossible and creates a block or routing loop.
This is because you need to use your normal ISP/LANgateway to hit the OpenVPN server if it is remote/offsite as is usually the case. So if you are connected to the OpenVPN through say a tun0 device and your routing is set to connect to the OpenVPN&nbs........
iptables -t NAT -A PREROUTING -s 220.127.116.11/24 -j DNAT --to-destination 10.10.10.1
iptables v1.4.7: can't initialize iptables table `NAT': Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.
# it is case sensitive "nat" and DO NOT use "NAT" or you will get this error!
iptables -t nat -A PREROUTING -s 18.104.22.168/24 -j DNAT --to-destination 10.10.10.1........
This error is commonly due to Java security or TLS settings but there is a second issue with forwarded ports that also causes it.
1. Java Security/TLS Settings issue:
This article has the solution to change them all in Linux automatically
2. Port Forwarding Issue if your Avocent DSR is behind NAT/private IP........
iptables -t nat -A OUTPUT -m addrtype --src-type LOCAL --dst-type LOCAL -p tcp --dport 3306 -j DNAT --to-destination ip.ip.ip.ip
iptables -t nat -A POSTROUTING -m addrtype --src-type LOCAL --dst-type UNICAST -j MASQUERADE
sysctl -w net.ipv4.conf.all.route_localnet=1
Make sure you substitute "ip.ip.ip.ip" for your real public IP and also the "--dport 3306" for the port you want to forward.
Finally run the sysctl command and........
The following assumes the computer is local/physical to you and/or it always has a LANIP so it can be accessed on site without having a default gateway.
The key to this is not to set a default gateway for your computer or you can set a script on boot or other time to delete the gateway (where eth0 is the NIC you are using):
route del default eth0
22.214.171.124 is the VPN server you connect to
192.168.1.1 is your........
If you are getting this error from Pluto/IPSEC it is almost always due to a routing or NAT issue.........
iptables -t nat -A PREROUTING -p tcp -m multiport --dports 80,443,2068,8192 -j DNAT --to-destination 192.168.1.175
Just adjust the "--dports" to the ports you need and the --to-destination to the destination IP (note it must be on the same network as the server running iptables........
iptables -t nat -A PREROUTING -p tcp -m tcp -d 192.168.2.1/32 --dport 3389 -j DNAT --to-destination 192.168.5.2:3389
iptables v1.4.7: can't initialize iptables table `nat': Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.
The above is often because you don't have the correct modules loaded on the hostnode or enabled for the container but in some cases it's actually a weird openvz setting.
-A PREROUTING -d 126.96.36.199/32 -p tcp -m tcp --dport 1050 -j DNAT --to-destination 192.168.1.50:3389
The above forwards port 1050 on IP188.8.131.52 to 192.168.1.50 port 3389 (you can obviously edit things to meet your needs).........
-A PREROUTING -p tcp -m multiport --dports 10000,18080,13306 -j DNAT --to-destination 192.168.5.83........
iptables -t nat -A PREROUTING -p udp -m multiport --dports 20,123,443 -j REDIRECT --to-port 53
getsockopt failed strangely: Invalid argument........
This is important if you need public access to internal IPs such as at your office and don't want to use a VPN just to SSHinto different servers:
Below forwards the port "10001" to the IP184.108.40.206 on port 22 (of course adjust it to your needs).
iptables -t nat -A PREROUTING -p tcp --dport 10001 -j DNAT --to-destination 220.127.116.11:22
Remember to enable MASQUERADE on your NAT IPs or they won't be able to talk to the outside world (........
This is something I often setup for clients because it's very helpful for people in datacenters, this allows custom OS installs on demand, you can customize it more by using kickstart etc.. but here's a base I use before customizing more:
This little script below will install everything you need to get booting by PXE Linux.
It also assumes you set a local IP (be sure not to overwrite your existing IP) on eth0:0 (note the :0) as 192.168.1.10 and it........
I used the suggested script to bridge from OpenVPN and it took my client's server off-line! Don't ever use their "sample" scripts if you don't have another way of accessing the server than SSH.
I actually found it easier to use iptables to tell it to route IPs based on a certain subnet to route through eth0:
iptables -t nat -A POSTROUTING -s 192.168.200.0/24 -o eth0 -j MASQUERADE
Replace "192.168.200.0/24" with your subnet of cour........
This may not apply to everyone but here is what happened to me.
One day my IP connectivity for one container went dead, I could ping the hostnode from it and the hostnode could ping it but there was no external routing. I restarted the network service but it didn't help.
I checked the routing table inside the VPS and the host and everything looked normal. Iadded another different IPon the same subnet to the container and it worked. Right away I st........
Remember to replace "eth0" with your NIC device although usually it will be eth0.
Replace 192.168.1.1 with your default gateway, remember you can also add multiple gateways by adding a second/different default gateway.
Kernel IP routing table
Destination Gateway Genmask&nb........
It's not all about the speed.I'd also thought I'd mention that speed is not everything. Routing is the key, because if one router you hit is slow then it doesn't matter how fast your connection is. I have found that locally, Telus has much better routing than Shaw (although I have not yet tested their new DOCSIS network).
There are also some countries such as Sweden that offer high speed connections, but the high speed only applies locally. The reason is that man........
Basic Port ListingHopefully someone finds this useful or at least interesting.
Name Port Protocol Description
Small services ........