I have been re-reading the posts again and I have one question. I believe what Chuck says is true about NAT outbound changes the source address, not the destination address.
So.... Would it be possible to change the destination address on the inbound side ? For example. Let say I have a web server behind my router doing NAT. 192.168.75.105. How would I tell the router to redirect connections going to 209.165.166.59 port 80 to go to 192.168.75.105 port 80. So I would be using the private address on the inside but still want the public IP address to be used by outside world. Would this not be changing the destination address ? Can this actually be done ? Thanks Michael ""Chuck"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > hhmmm..... > > as I understand the original question, each workstation in the network in > question is hard coded for DNS. > > So, if for example, my machine is hard coded for DNS server 207.126.96.162 > ( my ISP DNS server ) and I change ISP's, and make no changes to my > workstation, then any DNS request will have a destination address of > 207.126.96.162 > > The question, as I understand, if how to change that destination address > without making workstation visits. > > Policy routing can change next hop, but not destination address. NAT > outbound changes source address, not destination address. > > Unless there is a packet interceptor that takes all DNS requests, and > physically changes the destination address, the user has few options. > > Again, IF the former ISP does not restrict DNS requests to its own address > space, i.e. accepts DNS requests from anywhere, then there is no problem, > and no changes need be made. > > However IF ( and this would be good practice for a lot of reasons ) the > former ISP does indeed restrict DNS requests to source addresses within its > own space, then there will have to be additional changes on the user > network. > > This whole discussion illustrates why people SHOULD follow best practice > from the get go. If they want to hard code IP's, then I believe DHCP can be > configured so that it provides only DNS info and default gateway info, for > example. the people who have insisted that their network hard code > everything are now learning the hard lesson. > > Chuck > > > ""Priscilla Oppenheimer"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > At 05:11 AM 2/18/02, Godswill HO wrote: > > >You can still use your former ISP's DNS records while using the new ISP's > > >bandwidth. It does not matter who owns the DNS server. Everybody have > access > > >to it once they are in the internet. Except when they are specifically > > >filtered. > > > > > >The only drawn back is that, Your new ISP have to forward the packet in a > > >round trip to the old ISP's network through the internet before they are > > >resolved and sent back to you machine, > > > > It would depend on what records they are accessing. If the users are going > > to the Internet and accessing sites such as www.cisco.com and > > www.groupstudy.com, for example, the DNS queries don't have to go back to > > the original ISP. > > > > >had it been you are using the DNS of > > >your new ISP, these request would stop there. Do not loose your sleep, > > >because at the worst these delays are in milisseconds and not easily > > >noticeable by the eye, more each machine have a cache so it does not > forward > > >every request. Great if you have a Cache Engine to compliment the > machine's > > >cache. > > > > > >Whatever, you are kool and everything will be fine, switch to your new > ISP > > >and enjoy. > > > > > >Regards. > > >Oletu > > >----- Original Message ----- > > >From: Michael Hair > > >To: > > >Sent: Sunday, February 17, 2002 8:07 PM > > >Subject: DNS Request Redirection [7:35703] > > > > > > > > > > I was wondering what is the best way to take care of the following: > > > > > > > > I have been using a private address space behind a Cisco 4500 router > > > > connected up to our current ISP using NAT, now we want to move our > > > > connection from our current ISP to a new ISP with better bandwidth. My > > > > problem is that we don't want to change all our client machines TCP/IP > > > > settings, which are all static, for some reason or another they were > all > > > > setup to use our ISP's DNS. Not my idea but that another problem. So > how > > >can > > > > I setup our router to forward requests looking from our current ISP's > DNS > > >to > > > > our new ISP's DNS without touching all the client machines. > > > > > > > > Would the best way be to use policy-base routing? > > > > > > > > Would a static route work? > > > > > > > > Could I use a static route under NAT? > > > > > > > > If someone could proved me a sample of how you could do this I would > be > > > > greatful... > > > > > > > > Thanks > > > > Michael > > >_________________________________________________________ > > >Do You Yahoo!? > > >Get your free @yahoo.com address at http://mail.yahoo.com > > ________________________ > > > > Priscilla Oppenheimer > > http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35812&t=35703 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
