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Wow, I am surprised. I recently had to migrate my mailserver from my datacenter to the cloud. I lost the original IP address as a result. The new IP address got

Wow, I am surprised. I recently had to migrate my mailserver from my datacenter to the cloud. I lost the original IP address as a result. The new IP address got flagged immediately on gmail and everywhere else. I setup SPF and DKIM, that seems to fix the issues with the big guys. However on comcast and others I still got throttled for quite a bit. i had to request csi.cloudmark.com to unblock the ip..

mikeash 9y ago
I wonder if you happened to inherit an IP address from someone who was up to something less than savory.
- TheOtherHobbes 9y ago
  That would be my guess. I run an email server with ten domains on it. Hotmail blocked me once, but I had no problem getting that lifted. No other issues for over five years now. I have more of a problem with mail going the other way. I use a number of online spam traps to avoid spam, and my gf's Yahoo account often gets bounced by them. Specific Yahoo servers regularly get flagged for spam, and if you're using a Yahoo account your mail will be filtered by many, many servers if it's sent from one of those IPs.
- seanp2k2 9y ago
  Oftentimes, poorly-managed VMs / VPSes get infected with scripts / botnet software and start blasting out spam. It takes a long time for IP reputation to recover, esp. under the same owner info on the netblock. Regarding inbox deliverability from dynamic IPs (like you'd have with a residential connection), it might work sometimes for short messages with no attachments to people you've corresponded with before, but I wouldn't expect general deliverability to be very good. You have the same problem with botnet infections / malware-based spam here as well; home PCs are much more likely to get infected with that kind of stuff (though WordPress exploits are VERY common on servers), so many people running mail servers will just straight up block dynamic IPs from big ISPs and assume that nothing of value was lost. Personally, for low-volume mail such as what a home server might send regarding maintenance or alerts, I'd recommend using a service like mailgun and hooking up to that with SMTP. It's a lot easier than running your own mail server, you won't have to deal with inbound spam if you're only sending, it works well with minimal setup, they guide you through each step, etc etc.
brazzledazzle 9y ago
It was a long time ago so my memory is a bit fuzzy, but if I remember correctly it was fairly straightforward. It was right before and as SPF really became worth doing. The thing that would get a lot of my customers running their own mail was the PTR not matching the name presented by the mail server and/or that name not being listed in the MX records for the domain it was relaying mail for. I did have to deal with the occasional IP that had been blacklisted on RBLs and that could be a pain the ass and typically the first order of business was actually blocking outbound SMTP except from their mail server. Those were the days that I don't miss.

mikeash 9y ago

I wonder if you happened to inherit an IP address from someone who was up to something less than savory.

TheOtherHobbes 9y ago
That would be my guess. I run an email server with ten domains on it. Hotmail blocked me once, but I had no problem getting that lifted. No other issues for over five years now. I have more of a problem with mail going the other way. I use a number of online spam traps to avoid spam, and my gf's Yahoo account often gets bounced by them. Specific Yahoo servers regularly get flagged for spam, and if you're using a Yahoo account your mail will be filtered by many, many servers if it's sent from one of those IPs.
seanp2k2 9y ago
Oftentimes, poorly-managed VMs / VPSes get infected with scripts / botnet software and start blasting out spam. It takes a long time for IP reputation to recover, esp. under the same owner info on the netblock. Regarding inbox deliverability from dynamic IPs (like you'd have with a residential connection), it might work sometimes for short messages with no attachments to people you've corresponded with before, but I wouldn't expect general deliverability to be very good. You have the same problem with botnet infections / malware-based spam here as well; home PCs are much more likely to get infected with that kind of stuff (though WordPress exploits are VERY common on servers), so many people running mail servers will just straight up block dynamic IPs from big ISPs and assume that nothing of value was lost. Personally, for low-volume mail such as what a home server might send regarding maintenance or alerts, I'd recommend using a service like mailgun and hooking up to that with SMTP. It's a lot easier than running your own mail server, you won't have to deal with inbound spam if you're only sending, it works well with minimal setup, they guide you through each step, etc etc.

brazzledazzle 9y ago

It was a long time ago so my memory is a bit fuzzy, but if I remember correctly it was fairly straightforward. It was right before and as SPF really became worth doing. The thing that would get a lot of my customers running their own mail was the PTR not matching the name presented by the mail server and/or that name not being listed in the MX records for the domain it was relaying mail for. I did have to deal with the occasional IP that had been blacklisted on RBLs and that could be a pain the ass and typically the first order of business was actually blocking outbound SMTP except from their mail server. Those were the days that I don't miss.