Shakespeare answered your question some centuries back in Romeo Juliet Act II Scene II.
Right now I don’t particularly care about what a provider names their hosts, my filters tend not to care either unless it is a block based on those hosts. Not sure if I count as old fashioned, only been doing this stuff since around 98. From: mailop <[email protected]> on behalf of Hans-Martin Mosner via mailop <[email protected]> Date: Tuesday, 17 June 2025 at 3:19 PM To: [email protected] <[email protected]> Subject: Re: [mailop] iphmx.com - who owns that server (SPF fault) Not directly related, but how do people feel about those mail-as-a-service providers who basically hide their mixed bag of legitimate and abusive customers behind anonymous names? My old-school thinking is that I want to know who I'm talking to (or rather, who's mailserver my mailserver is talking to). Is this completely outdated? Cheers, Hans-Martin Am 17. Juni 2025 11:10:17 schrieb sebastian via mailop <[email protected]>: Anyone that knows how to get in touch with the admins on iphmx.com? Getting a lot of incoming SPF rejects on iphmx.com (mail destined for me, but rejected because sender SPF is faulty) - who owns that server? The thing is that iphmx.com seems to be a MaaS infrastructure who tells clients to use exists: as SPF records. Like: exists:%{i}.spf.hc2347-76.eu.ipmx.com One example: 23.90.102.86.spf.hc2437-76.eu.iphmx.com The problem is that these resolve to a private IP (172.0.0.2) which causes SPF failures due to DNS rebinding protection. Returning private IP adresses for external use is a big no-no. Works well for DNSBLs because in those situations its easy to configure a exception for the DNSBL server. Not so easy to configure an exception for all SPFes. Recommended DNS configuration change: Have the A record return its own IP: 23.90.102.86.spf.hc2437-76.eu.iphmx.com IN A 23.90.102.86 Best regards, Sebastian Nielsen, owner of sebbe.eu _______________________________________________ mailop mailing list [email protected]<mailto:mailop%40mailop.org> https://list.mailop.org/listinfo/mailop
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