I have a virtual network which is vmnet2 using the 10.0.2.0/24 network, I want my Linux server to be able to ping the default gateway.
I have set the Linux eth1 values to be
IPADDR="10.0.2.50"
NETMASK="255.255.255.0"
BOOTPROTO="none"
ONBOOT="yes"
In the etc/sysconfig/network
GATEWAY="10.0.2.1"
However, when I attempt to ping 10.0.2.1 the destination host is unreachable. I've restarted the network with service network restart but to no avail.
Destination Gateway Genmask Flags Metric Ref Use Iface
10.0.2.0 255.255.255.0 U 1 0 0 eth1
default 10.0.2.1 0.0.0.0 UG 0 0 eth1
The first row is the ipaddress and the second is the default gateway
Please make sure below,
Bridge the connection from your desktop .
You should be able to ping your Virtual machine IP from the parent machine where you have hosted the same.
Make sure you should not have any iptables rules configured that are constraing your connectivity.
This seems to enough , i have made similar setup recently.
Thanks,
Jain
You should add DEFROUTE=no in your eth1 configuration.
Related
I've a virtual NIC of type NAT on my Ubuntu 20.04 virtual machine which connects it to the internet via host. For some processing, I need to route all incoming and outgoing packets via a program I've to write. For example, assume that I've to drop some packets and don't let them go out of the VM.
For this, I created a dummy interface with the following:
modprobe dummy
ip link add tun0 type dummy
ifconfig tun0 up
For all traffics not to go directly through the NIC, I added:
ip route add default dev tun0
Now everything is ok. For example when I
ping 4.2.2.4
, I see that the ping is not answered when my program is not running and is answered properly when it's running. The program works like a bridge between enp0s3 and tun0 for now. The whole traffic is routing through my program. Just a problem exists, name resolution. That's when I
ping google.com
, the name can't be resolved. The route table now is as follows:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 0.0.0.0 0.0.0.0 U 0 0 0 tun0
0.0.0.0 10.0.2.2 0.0.0.0 UG 20100 0 0 enp0s3
10.0.2.0 0.0.0.0 255.255.255.0 U 100 0 0 enp0s3
169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 enp0s3
Of couse if I
sudo route del default
, the name resolution takes place via the NAT adapter through the host properly. Please let me know what's wrong with the name resolution in this situation.
I have a VM in Azure with Ubuntu 19.04 and 4 NICs, each one has a public IP attached to it, as an example, this is the second NIC:
As you can see, it has public IP 191.234.186.19.
My objective is to be able to access the internet from each NIC with a different IP address, but inside the VM I'm only able to access it with the first network eth0.
Looking at # route -n I get this output:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.0.0.1 0.0.0.0 UG 100 0 0 eth0
10.0.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
10.0.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth2
10.0.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth3
10.0.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
168.63.129.16 10.0.0.1 255.255.255.255 UGH 100 0 0 eth0
169.254.169.254 10.0.0.1 255.255.255.255 UGH 100 0 0 eth0
I tried to add routes for the other NICs with the following commands:
sudo ip route add default via 10.0.0.1 dev eth1 metric 101
sudo ip route add default via 10.0.0.1 dev eth2 metric 102
sudo ip route add default via 10.0.0.1 dev eth3 metric 103
But again I still can't connect to the internet with these NICs, only eth0.
Am I missing something? Should I need to change/configure anything else to make this work?
For completeness, I'm using this command to test the connectivity:
curl --interface eth1 api.ipify.org?format=json -w "\n"
And my VM is the same as the one in this article: article
I suspect you might need to
1) define new routing tables for your 2nd, 3rd and 4th interface,
2) add default routes to those tables
3) and define rules to ensure return packets always get routed back into the same interface the originating packets were sent from.
There are a few examples out there for your reference (for example this and this).
I'll just point out a couple of points that you might find helpful when setting this up for your specific case:
iproute allows you to maintain multiple routeing tables. To instruct the OS to utilise different routing tables you need to define rules that in most simplistic form will enforce the use of routing table corresponding to the interface that initiated the connection.
It looks like only eth0 has a default gateway. You cannot comunicate outside the local network without a default gateway
A bridge brOnline is connected to eth0 which provides access to the LAN / Internet. The setup is archived within modifying /etc/network/interfaces like below.
Why? The aim of this adventure is establish a virtual network between several virtual machines and the system hosting the virtual bridge an the virtual machines (host).
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet dhcp
auto MyBridge
iface MyBridge inet dhcp
bridge_port eth0
bridge_stp on
bridge_fd 0.0
How can I connect to the bridge from my host?
One important thing: Adding eth0 to the bridge makes it somehow unavailable to the host!
So before adding the interface eth0 to the bridge, which magic was connected to eth0 which enabled my browser the access to the local network? Can or how can I connect this magic to the bridge to have access to the LAN and can talk to the other clients connected to the bridge?
The attempts have been wrong. For the host it is not necessary to connect over an tap-device to the bridge, it has the abilety to connect directly to the bridge. In Other words if you set your default route to bridge connecting to the gateway, than you can connect to the LAN-Interface too.
# see actual settings
# The displayed via is the default gw which may be provided by your dhcp
ip route
default via 42.69.42.69 dev eth0
...
# delete the default route, otherwise error: "file exists" will show up
sudo ip route del default via 42.69.42.69 dev eth0
# Add your bridge as default route
sudo ip route add default via 42.69.42.69 dev brOnline
# check
ip route
default via 10.13.0.10 dev brOnline
ping/ssh to the outside are possible, also firefox is working with those settings.
Hint:
Those changes are not permanent. To do so, you need to edit /etc/network/interfaces.
I'm still not able to ping to the other VM's and vice versa, but this might be an other topic.
I have setup a Debian guest and I am messing around with it to learn more about VirtualBox, Debian, and later after that is done I'll be messing around with a NodeJS server on it.
After a while I noticed I couldn't do some things with it when I had a Bridged adapter setup for the VM. NPM would not install packages because it timed out. I tried running "w3m google.com" and even looked up google.com's ip to check for a DNS issue.
No matter what, I cannot connect to any form of internet. But I can ping anything just fine. I can ping google, npmjs.org, etc.
Thanks for the assistance.
Update: I have been working on this more today, Newer router, asus, I read that people were having issues with belkin routers with bridged adapters so I switched, the asus is new anyways.
The host is connected via ethernet wire.
The VM shows up on the router just fine, And I connect to that device with the IP given by the router just fine. but I still cannot connect to google.com or anything.
This is too long to explain in a comment. Below is how the bridged adapter works.
Yet, if you can ping from the guest debian that means some form of DHCP happened and you must have and IP (which is a different IP from the host machine). I'd check router configuration to see if you're not allowing/disallowing specific MACs and/or IPs from the usage of TCP/UDP protocols (that is a measure some people use on their routers).
Bridged adapter
A bridged adapter on VirtualBox simulates as if there was a bridge (well it is easier to think of this as a hub) on the cable connection to your (host) actual machine. Even if the connection is over wireless the simulation is similar.
For (almost) all purposes the guest (debian) and the router the host machine is connected to are connected directly. Have separate MAC, separate IP, they even give separate ARP requests.
router <---> host machine running VirtualBox
^
|
+-----> guest machine running Debian
This is done by sending packets with a different hardware address (you can configure the hardware address in the adapter).
You need to configure the guest system (Debian) to connect to the network as if it was a separate machine. For example, if you use a WPA connection from the host machine you need to configure WPA (including the username and password) in the guest machine.
I am not an expert, but after some research I could solve a similar problem. I have a Mac hosting a Debian server. I used Bridged Adapter on interface en0 in my Mac.
1) My Mac is running on 192.168.10.101. I know that because I run the command:
ifconfig -a
and the interface en0 shows that IP
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 6c:40:08:98:72:4c
inet6 fe80::6e40:8ff:fe98:724c%en0 prefixlen 64 scopeid 0x4
inet 192.168.10.101 netmask 0xffffff00 broadcast 192.168.10.255
2) Running netstat command at my Mac:
netstat -nr
Internet:
Destination Gateway Flags Refs Use Netif Expire
default 192.168.10.1 UGSc 296 142 en0
I see that the Mac Gateway is on 192.168.10.1
3) Mac and Debian must be in the same segment as the Gateway, I mean 192.168.10.xxx. So I decided that my Debian must run on the static IP 192.168.10.115.
I edited /etc/network/interfaces file at my Debian server to look this way:
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
source /etc/network/interfaces.d/*
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
allow-hotplug eth0
iface eth0 inet static
address 192.168.10.115
netmask 255.255.255.0
gateway 192.168.10.1
dns-nameservers 8.8.8.8 192.168.10.1
Then I did ping from my Mac and ping from my Debian and they answered Ok. I also have access to internet from Debian, because I have the same Default Gateway as my Mac.
root#debian64:/home/myuser# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default TEW-711BR 0.0.0.0 UG 0 0 0 eth0
link-local * 255.255.0.0 U 1000 0 0 eth0
I hope it helps and if anybody have better explanations I would like to learn.
I have 2 local networks (2 offices connected with openvpn)
Network 1:
network 192.168.1.0/24
gateway 192.168.1.101
Network 2:
network 192.168.2.0/24
gateway 192.168.2.10
in network 192.168.1.0/24 I have 2 servers - 192.168.1.180 and 192.168.1.183
first run on Debian 6 and second one on Archlinux (yes, I know it is bad choice for servers). I have no firewall on the servers.
everything works fine, clients from 192.168.2.0 can connect to computers in 192.168.1.0 and back. Except one of servers - 192.168.1.180 (Archlinux). I can't connect to it and can't connect from it to any computer in 192.168.2.0. No ping, no traceroute.
output from 192.168.1.180:
route -n
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.1.101 0.0.0.0 UG 0 0 0 eth0
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
i run tcpdump on the gateway (192.168.1.101) and ping on 192.168.1.180 and get this:
tcpdump src 192.168.1.180
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
14:23:57.354061 arp who-has 172.19.155.1 tell 192.168.1.180
14:23:58.357354 arp who-has 172.19.155.1 tell 192.168.1.180
...
why it looks for 172.19.155.1? I don't know what this strange IP means. I have no networks like this, no GW, nothing.
if I run ping on all other computer (for example ping from 192.168.1.183) I get:
tcpdump icmp
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
14:29:36.834731 IP 192.168.1.183 > 192.168.2.10: ICMP echo request, id 3216, seq 1, length 64
14:29:36.956211 IP 192.168.2.10 > 192.168.1.183: ICMP echo reply, id 3216, seq 1, length 64
No one looks for this strange IP except 192.168.1.180. I cleaned arp table on 192.168.1.180 but nothing helps.
it looks like you have a default gw configuration exists on your server x.180/24 which points to 172.19.155.1. So, the server assumes all the traffic has to go via 172.19.155.1 and trying to resolve the gw. Look for a default gw configuration in your system, something like this
0.0.0.0 0.0.0.0 172.19.155.1
use ip route xxx
You are able to see the packets in x.101/24 because it is an ARP request, which is broadcast MAC and you will see it on all directly connected devices.
Things I would do/check:
Make absolutely sure that I don't have a second interface going somewhere (ifconfig -a should do it)
I know, it's unlikely... but any chance a routing protocol is enabled on that server? You would see the routes in your routing table, though... which I understand is not the case.
Run a grep on /etc and wherever you have config files for 172.19.55.1
Just my 2c.
I've solved the problem. Not really solved, but at least it works now. The server must work 24/7 but it was my last chance and I rebooted it )) All work was stopped for 30 min but it was worthy of it.
I really don't understand wat happened with it. Some mystic problem.