
aculver at uwo
Jun 30, 2009, 6:33 AM
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We are looking to expand SPF records to several of our subdomains and clients' domains. We have 2 IP addresses which send outbound mail, which would be the same for most of our clients and subdomains. Rather than list these IPs in the SPF records for each client/subdomain, I think using include: may be more appropriate in case we need to change the IP in the future. Then I got wondering, should I do really have all these other domains include our top domain? What if we want to allow few more IP addresses to send mail as @uwo.ca? I don't want to authorize that IP to send mail as every other domain that's including us. This is our current SPF record: uwo.ca "v=spf1 ip4:129.100.74.146 ip4:129.100.74.147 ~all" I'm thinking of laying things out in the following way: _spf.uwo.ca "v=spf1 ip4:129.100.74.146 ip4:129.100.74.147 ~all" uwo.ca "v=spf1 include:_spf.uwo.ca ~all" its.uwo.ca "v=spf1 include:_spf.uwo.ca ~all" This way its.uwo.ca (and others) wouldn't need to update their records if we had to change our outbound mail servers and we could add additional entries to uwo.ca without affecting all the other domains. My only concern is the extra lookups caused by include. Is this a big deal? Would others recommend the setup I described? The description of how include works is also a bit unclear. If _spf.uwo.ca was to end with a "-all", would an SPF check on its.uwo.ca result in a FAIL or SOFTFAIL? I haven't tested this myself. Thanks in advance, Andrew ------------------------------------------- Sender Policy Framework: http://www.openspf.org Modify Your Subscription: http://www.listbox.com/member/ Archives: https://www.listbox.com/member/archive/1020/=now RSS Feed: https://www.listbox.com/member/archive/rss/1020/ Powered by Listbox: http://www.listbox.com
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