Newely created SPF record

[Mike From Markham]

I have created a SPF record but am unsure if I need to create this for each domain or just the domain of the mail.myserver.ca

For example I have

mail.myserver.ca

I also have
company1
company2
company3

Should I have each company create there own spf entry? Or as I understand it all thats needed is mail.server.com as that is my only MX server.

TXT myserver.ca 4 hrs v=spf1 a mx ip4:123.123.123.123 ip4:70.70.70.70 include:myserver.ca ~all

Record: v=spf1 a mx ip4:123.123.123.123 ip4:70.70.70.70 include:myserver.ca ~all
Prefix Type Value Prefix Desc Description
+ a Pass Match if IP has a DNS 'A' record in given domain
+ mx Pass Match if IP is one of the MX hosts for given domain name
+ ip4 123.123.123.123 Pass Match if IP is in the given range
+ ip4 70.70.70.70 Pass Match if IP is in the given range
+ include myserver.ca Pass The specified other domain is searched for an 'allow'.
~ all SoftFail Always matches. It goes at the end of your record.

For referance
70.70.70.70 is my mail.myserver.ca 123.123.123.123 is just where my website is hosted and has nothing to do with sending emails out of (I will probally remove that but got auto generated)

Questions, should include or any of the referances above be mail.myserver.ca?

Thanks!!

[j2b]

As to my understanding, SPF records state which servers coud send out e-mail on behalf of exact domains. In such case, if your companies have different domains, you have to create SPF records for each of them in their DNS zone.

But to my knowledge I could not gain any benefits of such, as the usage or benefit of SPF data is really tied up to servers, which are not yours. E.g., if they use or take in mind such records. And more, if your users use mobile clients with ISP connections, it'll mean, that you have to remove specific servers from your SPF record, or SPF aware servers will not receive such mobile emails, if your users send them out from their ISPs MTAs.

SPF: Tools

[lytledd]

it'll mean, that you have to remove specific servers from your SPF record, or SPF aware servers will not receive such mobile emails, if your users send them out from their ISPs MTAs

All that really means it that you force your users to send out your MTA, and use port 573 (SSL) to by-pass those ISPs that block port 25

Doug