Alias IP

[Zachár Balázs]

Glenn Satchell írta:
>> X-Original-To: dhcp-users at webster.isc.org
>> Date: Mon, 20 Nov 2006 15:11:34 +0100
>> From: Zachár Balázs <zachar at direkt-kfki.hu>
>> To: dhcp-users at isc.org
>> Subject: Alias IP
>> X-archive-position: 2311
>> X-ecartis-version: Ecartis v1.0.0
>> X-original-sender: zachar at direkt-kfki.hu
>> List-software: Ecartis version 1.0.0
>> X-List-ID: <dhcp-users.isc.org>
>> X-list: dhcp-users
>>
>> Hello @list!
>>
>> I have the following problem:
>>
>> active/passive cluster with one virtual IP address...
>>
>> A node real IP: 192.168.1.2
>> B node real IP: 192.168.1.3
>> virtual common IP: 192.168.1.5
>>
>> So I have an alias IP address in my interface. The dhcp requests come to 
>> the alias IP (192.168.1.5) but the offers going out on the real 
>> interface IP (e.g. 192.168.1.2).
>> Maybe the problem:
>> If I give an IP with my real interface, and before the client would like 
>> to renew his IP address the cluster is failover, the dhcpd's IP address 
>> will change... But if I send the offers trough the alias interface, If 
>> the cluster fail over the IP address is still the same (the virtual IP)...
>>
>> Can I send the offers with my alias interface?
>>     
>
> You might be able to use local-address,however there are some side effects.
>
>   local-address 192.168.1.5;
>   
>   



I try it before i wrote my problem... It didn't help for me... If I use 
this, the dhcpd is only listen in the alias IP which is good for me, but 
not enough...





> man dhcpd.conf
> ...
>        local-address address;
>
>        This statement causes the DHCP server to listen  for  DHCP
>        requests  sent  to  the  specified  address,  rather  than
>        requests sent to all addresses.   Since  serving  directly
>        attached DHCP clients implies that the server must respond
>        to requests sent to the all-ones IP address,  this  option
>        cannot  be  used  if  clients  are  on  directly  attached
>        networks...it is only realistically useful  for  a  server
>        whose  only  clients are reached via unicasts, such as via
>        DHCP relay agents.
>
>        Note:  This statement is only effective if the server  was
>        compiled using the USE_SOCKETS #define statement, which is
>        default on a small number of operating systems,  and  must
>        be  explicitly chosen at compile-time for all others.  You
>        can be sure if your server is compiled with USE_SOCKETS if
>        you see lines of this format at startup:
>
>         Listening on Socket/eth0
>
>        Note also that since this bind()s all DHCP sockets to  the
>        specified  address, that only one address may be supported
>        in a daemon at a given time.
>
> regards,
> -glenn
>
>
>
>