Re: [gentoo-server] Interesting IP Aliasing Problem

[M Summers]

Thanks for the advice Konstantin.  To be honest the "crazy" option looks
very interesting, but perhaps for another day.  I think I may have found
my solution.  It occurred to me that I just needed to have a unique MAC
for my ISP's dhcp server, but not necessarily for the network proper. 
In that case, I can simply pass a "unique" CLIENTID to dhcpcd when I
call it, as in the following test (-T) example:

    # dhcpcd -T -I 00:GE:NT:00:RO:CK eth0:0   
    IPADDR='192.168.1.105'
    NETMASK='255.255.255.0'
    BROADCAST='192.168.1.255'
    ROUTES=''
    GATEWAYS='192.168.1.1'
    DNSSERVERS='DNS server IPs are here'
    DHCPSID='192.168.1.1'
    LEASETIME='86400'  
    RENEWALTIME='0'
    REBINDTIME='0'
    INTERFACE='eth0:0'
    CLASSID='dhcpcd 3.1.5'
    CLIENTID='00:GE:NT:00:RO:CK
    DHCPCHADDR='my:re:al:ma:ca:dd'

Now, of course, I didn't actually use 00:GE:NT:00:RO:CK as the CLIENTID,
but you get the point.

At this point the question becomes: Will I be able to use this with my
IP, not just my internal router?  I hope so, I will test very soon.

Another question is:  How do I add this to /etc/conf.d/net so that this
all occurs nice & clean whrn I start net.eth0?

Regardless, thanks for the assistance.  I will post with further news as
I learn.  Anyone with any experience with this subject, please know that
your past and future assistance is appreciated.

Cheers,
Summers





Konstantin Astafjev wrote:
> Hello M,
>
> Monday, December 3, 2007, 8:46:58 PM, you wrote:
>
>> I have a rather pressing issue with IP aliasing.  So, my ISP assigns IPs
>> via dhcp using the MAC address to bind it statically.   What I need to
>> do is get multiple static public IPs via their dhcp server.  My ISPs
>> reliance on dhcp presents an interesting problem.  How am I to acquire
>> multiple static public IPs from one NIC, say eth0, if their dhcp server
>> requires a unique MAC address per IP?  I have tried using macchanger,
>> but it doesn't work for aliases alone.  It changes the MAC for the main
>> interface, eth0, not eth0:{0,N}.
>>
>
> If I'm not mistaken you have 3 options:
>
>  - force your ISP make some static rules mac=some_IPs in their
>    switches/routers. I guess they forcing clients to use DHCP because
>    of "dhcp snooping" and "arp inspection" features helps them filter
>    alien ips&macs.
>
>  - take a simple switch and some NICs with different MACs.
>    Quantity depends on how many IPs do you need. ;)
>
>  - the craziest one: take vlan switch, on your NIC create some VLANs,
>    change MAC address on each VLAN.
>
> AFAIK, DHCP assigning a different IPs simultaneously on one MAC impossible.
>
>

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