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Spamgourmet doing reverse DNS lookups only via ipv6

PostPosted: Thu May 09, 2019 8:14 am
by lwc
The free service phplist.org has recently stopped sending notifications (e.g. in their forums) to Spamgourmet users.
I'm happy to announce it's now solved after my personal request to their owner!

But be aware it might explain why other services don't support Spamgourmet (I've bolded up the most surprising part):
Your mail host does reverse DNS lookups only via ipv6. We disable ipv6 by default due to infrastrudture software that we use not yet supporting it. This is the first time we’ve seen a host not support ipv4 for such lookups. Happy it’s fixed!

Re: Spamgourmet doing reverse DNS lookups only via ipv6

PostPosted: Tue Dec 24, 2019 7:50 pm
by larry
I think this affects many services. I've stopped getting email through SG from several sources, starting around early September.

Re: Spamgourmet doing reverse DNS lookups only via ipv6

PostPosted: Thu Jan 09, 2020 2:55 pm
by SysKoll
I am not sure how they reached the conclusion that the reverse DNS lookup is done in ipv6 only. Here is what I see from my prompt:

Code: Select all
$ nslookup
> server 8.8.8.8
Default server: 8.8.8.8
Address: 8.8.8.8#53
> gourmet.spamgourmet.com           
Server:      8.8.8.8
Address:   8.8.8.8#53

Non-authoritative answer:
Name:   gourmet.spamgourmet.com
Address: 216.75.62.102
> gourmet7.spamgourmet.com
Server:      8.8.8.8
Address:   8.8.8.8#53

Non-authoritative answer:
Name:   gourmet7.spamgourmet.com
Address: 216.75.62.102


8.8.8.8 is the Google DNS server. It resolves the gourmet7 address (which is the spamgourmet.com's mail gateway) back to its address. Can you ask your provider what he sees instead, if not this?

Re: Spamgourmet doing reverse DNS lookups only via ipv6

PostPosted: Sat Jan 18, 2020 8:40 am
by lwc
SysKoll wrote:Can you ask your provider what he sees instead, if not this?

SysKoll, you're back!

The provider replied the following:
Hi, I confirm, that the host resolves OK both ways using IP4 now. I can’t replicate the original issue.

That's great news! Could it be Josh fixed it without replying here?

Re: Spamgourmet doing reverse DNS lookups only via ipv6

PostPosted: Mon Jan 27, 2020 2:19 am
by SysKoll
That's great news! Could it be Josh fixed it without replying here?


Josiah fixes a few things, not sure about that one in particular.

Sorry for having been away from sg so long. Things have been a bit hectic.