Ifconfig alias

A

aiiR7

Hello there,

Well, I have a simple question about networking. I have several servers in a European datacenter, each server has only one network card. Few servers run as application, one of these servers is a database server. I don´t want to waste traffic, so all servers must communicate in a localhost to the database server.

Is it enough, if I do [cmd=]# ifconfig em0 192.168.1.x netmask 255.255.255.255 alias[/cmd] on all servers?

Maybe this way:

App servers:
Code: 
Server 1 "ifconfig em0 192.168.1.5 netmask 255.255.255.255 alias"
Server 2 "ifconfig em0 192.168.1.6 netmask 255.255.255.255 alias"
Server 3 "ifconfig em0 192.168.1.7 netmask 255.255.255.255 alias"
Database server:
Code: 
Server "ifconfig em0 192.168.1.10 netmask 255.255.255.255 alias"

Thanks in advance,
aiiR7
 
Yes, you can do it that way. You have to include the alias entries to /etc/rc.conf to make it permanent.

Something like this:
Code: 
ifconfig_igb0_alias0="inet 192.168.30.10 netmask 255.255.255.0"
ifconfig_igb0_alias1="inet 192.168.30.20 netmask 255.255.255.255"
ifconfig_igb0_alias2="inet 192.168.30.30 netmask 255.255.255.255

Or, the cleaner way:
Code: 
ipv4_addrs_igb0="xx.xx.xx.xx/26 192.168.30.81/24 192.168.30.82/24
 
Hi,

Yes, I know that with the rc.conf. I'll take the cleaner way, I thought so, too, but I have never tested it. Is it important to have a pf or any other packet filter to route traffic on the local network?

Thanks.
 
I'm using pf, because all of my servers have one NIC on each, and all of my jails are using private IP addresses. The host gets a public IP, so pf does all the routing between the host and the jails. As for the database which also resides in a jail, I only open up the database port for the web jails to access it. If all run locally, and you don't need to access the database from outside the network, then I don't think any routing is necessary.
 
Well, I need access from outside the network. Every server has a public IP address and an internal/local IP address. Each server will communicate via the internal/local IP address, because I can save a lot of traffic this way. Of course I need access from outside to the network, too, but that is not a problem.

So you think pf is important? If you want to know more, send me a PM.

That's my first step setting up a local network, sorry.

aiiR7
 
aiiR7 said:
I don´t want to waste traffic, so all servers must communicate in a localhost to the database server.
Click to expand...
You mean local network. Localhost is 127.0.0.1/8.
 
No problem, I wasn't sure if you understood the difference :e
 
SirDice said:
No problem, I wasn't sure if you understood the difference :e
Click to expand...

Hehe, sure :)

I had the same running via a switch in our old rack, but this is another way.
 
Hi again,

Well, I asked my hoster about this, because you don't want to rent a switch for the first time.

Hoster:

"Doing so would mean we still have to make an extra virtual lan in our network. Not using a second nic would mean internal data traffic would be billed if it exceeds your traffic limit"

Is that right?
 
That's possible, it depends on how and where they actually measure your bandwidth usage. It's possible they do this on the switchport. In that case it won't matter what network addresses you use, it always passes the same switch port, hence it always gets measured.

If those servers are in the same rack just add an interface and buy a simple switch to connect them. If the hoster allows it that is.
 
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