Reading the bug report, I see they have temporarily dropped SORBS. When I set up my email server, SORBS turned out to be useless because of false positives.
I see Dreamhost will give you a unique IP for $6. Kind of pricey considering a VPS from Digital Ocean and a few others can be had for $10. They come with a unique IP address. Another alternative is to use Gmail. Either free, or you can get a paid account that allows more control, not to mention DKIM and SPF back to your domain. I spent 15 years on a shared IP, getting blocked on and off. I believe there is no solution to being blocked as long as some spammer can use the same IP address. When VPS arrived, I got one and never looked back. However you need to spend time setting it up and playing sysadmin (mostly patching) . For some people, the additional fee that Dreamhost charges for a unique IP is the best solution. Original Message From: Tanstaafl Sent: Friday, June 17, 2016 6:11 AM To: postfix users Subject: OT: dnsbl.sorbs.net - help explaining to Mozilla list maintainers why outright blocking is bad Hello, I've been experiencing and on/off again problem with my shared dreamhost account IP block getting listed by SORBS. The only reason I know this is because apparently the Mozilla list maintainers have configured all of the Mozilla discussion lists to outright BLOCK based on being listed by dnsbl.sorbs.net. After querying where/how to request this be changed through the proper channels, I opened a bug with respect to the list infra owners, and explained to the best of my ability why outright blocking based on SORBS listing is bad: https://bugzilla.mozilla.org/show_bug.cgi?id=1280451 It was immediately closed with this response: "SORBS is an RBL service we use, and generally when you get listed its actually for a reason and usually we push back and have the ISP to request a delisting since you are placed on this list for a reason. Looks like what you are sending is from a dreamhost IP range, are you sending directly from a host? I would recommend using a mail relay or you could talk to dreamhost about asking them to get delisted" I responded requesting reconsideration, and re-opened it. Would appreciate some help. Their lists are the only reason I ever find out that dreamhosts IP block I'm on gets listed - none of the other 25+ lists I'm on have ever blocked because of it.