nanog mailing list archives

Re: ISP customer assignments


From: "Ricky Beam" <jfbeam () gmail com>
Date: Wed, 21 Oct 2009 17:37:02 -0400

On Tue, 20 Oct 2009 19:38:58 -0400, Bill Stewart <nonobvious () gmail com> wrote:
... If you've got a VPN tunnel device, too often the remote
end will want to contact you at some numerical IPv4 address and isn't
smart enough to query DNS to get it.

As I was told by Cisco, that's a security "feature". Fixed VPN endpoints are supposed to be *fixed* endpoints. Yes, it is a pain when an address changes, for whatever reason. But relying on DNS to eventually get the endpoint(s) right is an even bigger mess... how often is the name<->IP updated? how often do the various DNS servers revalidate those records? how often do the VPN devices revalidate the names? what happens when the dns changes while the vpn is still up?

I'll stick with entering IP addresses.

--Ricky


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