OpenStack neutron subnet - create port with ip address after network address - mariadb

I have this neutron private subnet 10.200.206.0/23
when I created a port using this subnet, it should give me 10.200.206.1 as I expected since nobody uses this .1 ip yet.
Instead it gave me 10.200.206.20
Note this subnet had been used previously and deleted all ports/ip that used by other instances. I am 100% that this ip 10.200.206.1 is not in-used.
DHCP is disabled.
Can we actually reset the old info from this subnet in OpenStack DB backend?

Once you start using a subnet, Neutron DB will keep track of used IP addresses and doesn't reassign until all the addresses are used once.
Easiest way to reset is to remove the subnet and recreate it again.

Related

What is an openstack port?

I am trying to map the notion of an openstack port to an IP abstraction. In the openstack documentation I see :
"A port is a connection point for attaching a single device, such as the NIC of a server, to a network. The port also describes the associated network configuration, such as the MAC and IP addresses to be used on that port."
So I assume a port must correspond to an IP interface (which in turn can map to a bridge, an ethernet interface or to one end of a veth link).
Is this a correct assumption? I am trying to figure out what IP abstraction maps to a loadbalancer port and I can't yet find it.
Thanks
Answering my own question (hopefully of help to others):
An openstack port corresponds to an ovs (or linnuxbridge) port that connects you up to a virtual network. A prefix of the port ID is used as a bridge name. You can create a port to a network and add it to a router.

CentOS - Wrong automatic ifconfig broadcast address

Running a Centos 5.11 machine with two network cards.
One is facing the internal network (private IP), the other the Internet (public IP).
Because we had some issues lately with it (ARP collision - but that's not the point here!), I started verifying its config. And I find out the broadcast set for the public IP is wrong.
IP is xxx.xxx.xxx.25
Subnet is 255.255.255.240
So basically we should have:
Network xxx.xxx.xxx.16
First IP xxx.xxx.xxx.17
Last IP xxx.xxx.xxx.30
Broadcast xxx.xxx.xxx.31
But the broadcast is automatically set to last host xxx.xxx.xxx.30
If I change it using command line, it is reseted back to the same IP once I do a service network restart...
I had to edit /etc/sysconfig/network-scripts/ifcfg-eth0 for the broadcast to stick to what I wanted.

Setting a networked pc to keep its IP

Is it possible to have one of our networked PC's to keep using the same IP address (192.168.1.54) so that if the master computer or a failure / shutdown etc happens then the system IP addresses are not reset so i don't have to update all the other pc's hosts files to this PC's new IP address?
You will need to make a reservation based on the MAC address of your network card. You can find this by typing "ipconfig /all" inside the command prompt.
The IP addresses can be reserved on your router or on your server depending on how they are distributed.
You should solve this in the DHCP server (typically in your router), make a reserved IP for the mac-address of the PC in question. Or you configure the PC to not use DHCP but configure a fixed IP. But that should be, if possible, an IP that is not in the DHCP range.

How to setup a bridge connection with vbox/vmware using a second wan ip on a dedicated server

I am using a dedicated server with a certain wan ip / netmask / gateway / nameservers.
I got a second wan ip to use with virtualbox i installed on the server.
I want to use bridge connection in virtualbox because i use some "servers" in it and want them to be able to be seen from internet .
I created a virtual network interface on the server and assigned the second ip to it.
It works , meaning i can ping that ip from outside.I setup virtualbox to bridge to that interface but i am stuck at what settings i have to set up in the virtual guest so everything will work.
Second ip has netmask 255.255.255.255 so i assume its a single ip situation and probably using gateway and nameservers of the server because i was given none of them with it.
I have to mention that first ip and second ip are not in the same subnet , nor is the gateway (e.g. XX.YY.ZZ.WW , ZZ is different between first , second and gateway ip)
Thanks in advance.
You have to unbind TCP and all other protocols and services on the hosts NIC that you want to use in VBox. After that, you can configure a bridged network connection using that interface. After that, you can set the IP and network settings in your virtual system. This has also been addressed in this post: https://serverfault.com/questions/136969/dedicate-a-nic-to-a-virtualbox-vm

AWS Connecting to instance in public subnet

I'm trying to SSH into a known good instance inside a new AWS VPN
Set up so far
Elastic IP connected to VPC instance inside public subnet
IGW associated with subnet with CIDR 0.0.0.0/0
Security Groups set up
Does anyone have any debug tips? Does the configuration matter?
Mostly want to know how to debug and isolate issues like this
Check your security group make sure your allowing the SSH port and also the CIDR for the inbound traffic to bind to that port.

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