[Haifux] Solved: Problems with the mailing list

Eli Billauer eli at billauer.co.il
Thu Jan 23 19:50:28 IST 2014

Hello everyone.

As some of you told me, there were problems with Haifux' mailing lists 
recently, in particular with those using Google's mail services, who 
didn't get the mails at all. Others have seen delays.

This has been solved now. This message will reach everyone (fingers 

I'm sincerely sorry for the inconvenience, specially those of you who 
missed lectures because of this. Please keep an eye on our site, if you 
don't hear from us for a while.

The root cause is that we moved server about a month ago, and it took 
some time to get the rDNS set up. This is done through a manual request 
from the service provider. Lesson learned: Don't switch server before 
the rDNS is set up, and don't start the transition near Christmas...

On top of that, the new service provider supplies an IPv6 address. 
Hurray! Well, not. The mail server used the IPv6 address to contact 
Google's mail server, which refused to handle the messages, saying 
"Service unavailable". I suppose that the reason is that haifux.org has 
forward and reverse DNS entries for IPv4 only, so the mail server 
considers our MTA to be a massive spammer. I solved it by turning IPv6 
off. Not politically correct, but is there any practical reason to 
support IPv6 these days?

I suppose that the right thing is to set up IPv6 DNS records and 
possibly an SPF record. But I can't see the reason to bother.

Thanks to Guy Edri for the crucial clue while sorting this out.

Sorry again,



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