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On Tuesday 13 July 2004 01:29 pm, Andrew G. Tereschenko wrote:
[Ralf Doeblitz]
If you are using dialup lines with a dynamically assigned ip address,
your ISP should publish a matching SPF record that you can include or
redirect to in your own SPF record.
If you have a static allocation, your ISP should notify you of any
changes well ahead of time (at least one week, better two or more) so
you can modify your DNS data accordingly.
Current Internet business is not simply ISP and client.
And current businesses hire responsible, knowledgeable, experienced network
engineers.
ISP can inform their reseller on address changes, but reseller can forget
to notify you/use your outdated email or simply ignore ISP warning, as
they will find it's not valuable.
Then SPF is the least of your worries.
As well your company administrator can be on two weeks Hawaiian Vacation.
Then SPF is the least of your worries.
Do you wish to create SPF records change burden simply because your ISP
decided to optimize their network?
Then SPF is the least of your worries.
BTW, single change in ISP IP allocation requires you to change your DNS
zone at least twice.
Once to list both old and new IP ranges, at second to remove old IP
range.
So change your SPF record twice. No biggy here.
SPF requires current and relevant information about complete mail routing
path to be stored in DNS.
What is this supposed to mean? Are we supposed to publish incomplete and
irrelevant information about complete mail routing path in DNS and expect
people to get the current and relevant information out of it?
This make impossible for ISPs to optimize their mail flow by using
additional outgoing MTA. For example Ukrainian ISP will be unable to use
dedicated Russian server to optimize traffic pattern for emails like
user(_at_)domain(_dot_)RU
SPF will not allow this because this will require ISP clients to list and
maintain Russian server address in their zone.
Adding additional Germany (*(_at_)*(_dot_)de, UK) or US servers will require
all
clients notified and forced to update their data. Or such an optimization
must perform SPF checks in advance - costly process :-(
If you outgoing mail policies change, you need to update your SPF records.
How else will receiving MTAs know about your change in policy?
- --
Jonathan M. Gardner
Mass Mail Systems Developer, Amazon.com
jonagard(_at_)amazon(_dot_)com
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