We have replaced MailChannels with an in-house relay system.
For well over a year the MXroute in-house relay system has been in the works. It started during an outage of the relay service that we had outsourced outbound email to. After a test had been in production for a few months, the release of this product had been shelved for a bit. However, we were sitting in a nearly complete product for quite some time.
For one week now we have been running purely on MXroute's internal outbound relay system. The results have been quite impressive. We have scaled it out and intend for this relay system to perform the same functions that you are used to, not seeing an impact to your delivery quality if someone sends spam through our service, and not seeing rejection if an IP is blacklisted. As of yesterday, a blacklisted IP should not occur all the way down the stack, and you should be safe from that.
The relay system works like this:
filter > relay2 > relay3 > filter2 / filter3 > multiple possible MailCheap relays
The hostnames for these are not exactly that, but the logic is that. If an email is rejected from relay2, it goes to relay3. If rejected from relay3, it goes to filter2 or filter3 (which ever is available) and is then scanned through a slightly more strict filter before being sent out by an outbound relay from our friends over at MailCheap.
Now, relay2 and relay3 both change hostnames and outbound IPs every hour, to continually work toward reducing any IP specific issues with rate limiting or reputation. They each have a failsafe function that is executed manually by us. That failsafe changes the hourly IP/hostname swap to another set of IPs/hostnames, in the event that the primary two see problems.
This is the next iteration of MXroute as a service, and it is a great day for us and for customers. It means that we can further sustain our low prices while continuing to ensure the quality inbox delivery (there will always be exceptions) that you are used to.