IP address changing,

[Walid]

Hi all
My company will change the ISP, which means we will have another set of IPs. The problem is they told use that the DNS table takes about 3 days to be updated. My question is how I can save our web and mail server during the transiet time. If I changed the IPs at once b4 the DNS update our address will point to nothing b4 the update, If this question looks silly to you guys, just forgive me I am a programmer not NT admin, but our admin choose to leave in very critical time, so I am treing to help as much as I can.
Thanks in advance. Walid Magd
Engwam@Hotmail.com

 

[wybnormal]

You could try a few things.. if you have a router and I'm sure you do.. run NAT on the router and "translate" the addresses back and froth..

2nd possiblity is enter a 2nd record in your DNS that points to the new IP but with the same name.. if I remember correctly, the DNS will try the first and then round robin to the 2nd? I read about this in WIndows 2000 magazine but my brain cells are fuzzy this early.

Add a second IP address to the NT server so it's multi-homed..( might be the easiest) plus a new A record in your own DNS.

Mike S
"Diplomacy; the art of saying 'nice doggie' till you can find a rock" Wynn Catlin

 

[Walid]

Hi Mike,
Thanks for your fast response, I have a Cisco router, so it will be great if you can guid me or recommed a source to follow the first method "run NAT on the router" by the way I don't know what is this NAT.
Thanks Walid Magd
Engwam@Hotmail.com

 

[peterve]

Setting the second IP in the DNS will work, but only in round robin (so it will only redirect the users 50% of the time to the correct website once your current IP goes away...)
You could also ask your provider to decrease the expiry time, so the transition only takes a very short time... Peter Van Eeckhoutte
peter.ve@pandora.be

 

[wybnormal]

You can use NAT( network address translation) where there is an "outside" IP set and then translated to an "inside" IP address. THis can be a static map for port 80 only..

204.80.80.3:80 nat outside IP( new serverIP) NAT nat inside ( old server IP:80)

!
interface Ethernet0
ip address 192.1.1.1 255.255.255.0
no ip directed-broadcast
ip nat inside
no cdp enable
!
interface Ethernet1
ip address 63.192.193.111 255.255.255.0 ; outside "real" IP
no ip directed-broadcast
ip nat outside
no cdp enable
!
!
ip nat inside source list 1 interface Ethernet1 overload
ip nat inside source static tcp 192.1.1.235 80 63.192.193.111 80 extendable; static map to old IP



Mike S
"Diplomacy; the art of saying 'nice doggie' till you can find a rock" Wynn Catlin