Using a Cisco 1800 series with DNS and public IP addresses??

kayasaman · ‎01-10-2010

Hi,

the question I am about to ask is pretty simple but since I've just graduated from a CCNA recently I am just a little unsure about how to acheive this!

I would like to use a Cisco 1800 series router as the main gateway in combination with a 2950 switch to provide the network foundation for a small data center which I am building.

Basically my issue is that I would like to assign public IP addresses to two NICs on a mainframe server, a Sun Microsystems Fire V480 which will run FreeBSD in combination with 'Jails' or OpenSolaris and Zones to provide a master/slave DNS setup.

Because of my lack of experience with this as I've never done it before I am wondering what the best way to acheive this is???

If perhaps I could use 2 of the switch ports on the 1800 for this and if so how? The 1800 has a layer2 managed switch built-in meaning that I could create a VLAN for the block of public IP's allocated but then if the routed port on the 1800 which most likely will be the ATM interface of the 1801, is within the same subnet the IOS will most likely complain.....

Is there anyway I can include the switchports in the same network path as the WAN interface?? Perhaps using a NAT outside definition if it's possible??

Currently I have a setup based around an 857W and one DNS server is open to the web but through NAT: http://www.optiplex-networks.com/lab/lab.html

I would appreciate any help or advice anyone has to offer :-)

Many thanks and best regards,

Kaya

Ganesh Hariharan · ‎01-14-2010

Hi Kaya,

For your requirement you can do a NAT configuration in you internet facing router to expose your server in internet.The best way is to achive is by Static NAT configuaration in your router.

Check out the below link for static nat configuartion hope this helps out your query !!

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080093f31.shtml

Regards

Ganesh.H

kayasaman · ‎01-14-2010

Thanks Ganesh!!

So... basically it's just what I'm doing now but instead of using

ip nat inside source static udp 10.10.10.10 53 dialer 0 53

I will need to use:

ip nat inside source static udp 10.10.10.10 53 123.123.123.123 53 extendable

ip nat inside source static udp 10.10.10.11 53 123.123.123.124 53 extendable

I have also in the mean time been told on the Bind mailing list that Bind will accept transmissions like this as I thought the the decapsulation and re-encapsulation of the router would cause a problem with the software!

So looks like all is good now :-)

Regards,

Kaya

Ganesh Hariharan · ‎01-14-2010

Hi kaya,

Natting only do your private ip to communicate to internet world and as per my thought binding of any software is with the physical ip address of the server and here that is your private ip so i dont think it should be a problem for your setup.

Hope that helps out your query !!

If helpful kindly rate your views !!

Regards

Ganesh.H

kayasaman · ‎01-14-2010

Many thanks Ganesh!! :-)

Your input is highly appreciated.

Best regards,

Kaya