# SPF best practice for shared IP

**URL:** <https://forum.dmarcian.com/t/spf-best-practice-for-shared-ip/1260>\
**Category:** Technical Help\
**Created:** [June 15, 2020, 1:11pm UTC](https://forum.dmarcian.com/t/spf-best-practice-for-shared-ip/1260 "2020-06-15T13:11:10Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![csasser](https://yyz2.discourse-cdn.com/flex036/user_avatar/forum.dmarcian.com/csasser/32/90_2.png) [@csasser](https://forum.dmarcian.com/u/csasser)\
**Post date:** [June 15, 2020, 1:11pm UTC](https://forum.dmarcian.com/t/spf-best-practice-for-shared-ip/1260/1 "2020-06-15T13:11:10Z")

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If I am on shared hosting should SPF record be more explicit like instead of using +a would it be better to use +a:example.com (with or without +)?

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**Author:** ![UffeA](https://avatars.discourse-cdn.com/v4/letter/u/b5e925/32.png) [@UffeA](https://forum.dmarcian.com/u/UffeA)\
**Post date:** [June 16, 2020, 2:01pm UTC](https://forum.dmarcian.com/t/spf-best-practice-for-shared-ip/1260/2 "2020-06-16T14:01:36Z")

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If the “a” without domain is in the SPF record for [example.com](http://example.com) it will be resolved as “a:example.com”, but if it is in the SPF record for [example.net](http://example.net), it will be resolved as “a:example.net”. So the answer depends on what you’re trying to achieve. If there’s a risk that the IP address changes, I’d use the specific “a:example.com” (or even more specific “a:mail.example.com”) mechanism and if the IP is known to be static, I’d use an “ip4” mechanism. The + sign is implicit, so it can be omitted.

Regards  
/Uffe