static ip address and ifconfig

Fbsd8 fbsd8 at
Sat Dec 29 21:16:11 UTC 2012

snip previous
> It still all depends on your configuration, it won't look any different 
> than a static private IP address shows when doing an ifconfig except it 
> will be the public IP.  Generally if you have a static IP you will have 
> to set it manually, and it won't get it via DHCP.  But I have worked 
> with some DSL connections though that assigned the static IP through a 
> DHCP reservation based on your modem/routers MAC address.  However that 
> would only work for a single IP.  If you get 25, you can assign those 
> with aliases to make a single server answer on the others as well, 
> common for servers hosting multiple https web sites.
> Here's an example with Aliases, its from a LAN with private range, but 
> would look no different except IPs if it was public range addresses.  
> This is from my web/email server (the very one this message comes from), 
> the secondary IP is for running jails, when testing upgrades.
> LAN: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 9000
>         ether 00:07:e9:09:be:4f
>         inet netmask 0xffffff00 broadcast
>         inet netmask 0xffffff00 broadcast
>         media: Ethernet autoselect (1000baseT <full-duplex>)
>         status: active
> Here's an example from a public range, pulled this from my pfSense box, 
> which is on a Cable Connection with a block of 5 static IP Addresses.
> vr1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
>     ether 00:0d:b9:1c:78:2d
>     inet netmask 0xfffffff8 broadcast
>     inet6 fe80::20d:b9ff:fe1c:782d%vr1 prefixlen 64 scopeid 0x2
>     nd6 options=43<PERFORMNUD,ACCEPT_RTADV>
>     media: Ethernet autoselect (100baseTX <full-duplex>)
>     status: active
> There's just a single IP set, though it does relay connections on other 
> IPs, using proxy arp to do this so there is no need for an alias to be 
> defined.

So your saying the ISP forwards any internet traffic for those static ip 
address to the on site "modem/router" MAC address which my service was 
previsioned to?

The ISP is sending DNS port 53 and DHCP port 67 traffic on each static 
ip address as well?

I can configure the on site modem/router to assign selected static ip 
address to a router's hardware port which is cabled to different PC's?

The PC's would only be seeing traffic for that selected static ip address?

The rc.config statement ifconfig_xl0="DHCP" on that PC would function as 

Now if I only had a on site "modem" with a single output port, then
all the static ip address would hit the NIC card it was cabled to?

So on the single FreeBSD system with NIC xl0 being cabled to the single 
port coming from the on site modem I would need ifconfig statements in 
rc.conf to select what static ip address I want to use for DHCP to 
automatically get the ISP's DSN ip address?  Please correct my syntax if 

If I wanted to use the remaining static ip address for other PC's on my 
private LAN I would have to have additional ifconfig statements in rc.conf?
or would I need a single statement for each alias? Please correct my 
syntax if wrong.

I would also have to configure my firewall to redirect those alias 
static ip address to the LAN ip address of the servers I want to target?

For some of the remaining static ip address i have not used yet, I would 
like to use them for jails. Using the jail option to provide the
interface name to bound to which automatically creates an alias for the 
jails ip address at jail start time and also removes it when the jail 
stopped. I can do this by creating the jail using one of the unused 
static ip address?

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