Where we filter your mail
DuoCircle filters mail in two regions: the United States and the European Union. The European Union cluster is in Frankfurt, Germany.
If you use our global MX records, or your custom MX record from the portal, we balance your mail across both regions. This is the right choice for most customers.
If you must keep your mail inside one region, use the regional MX records instead.
Which MX records do I use?
Every set has four records, one on each of our four top-level domains. Add all four.
| You want | Records to use |
|---|---|
| Both regions (recommended) | mx1.mailhop.org, mx1.mailhop.us, mx1.mailhop.co, mx1.mailhop.co.uk |
| European Union only | mx1.eu.mailhop.org, mx1.eu.mailhop.us, mx1.eu.mailhop.co, mx1.eu.mailhop.co.uk |
| United States only | mx1.us.mailhop.org, mx1.us.mailhop.us, mx1.us.mailhop.co, mx1.us.mailhop.co.uk |
The same four hostnames serve every service. Email Backup MX differs in one way only: your own mail server takes priority 10, and our records take the higher priority numbers.
Geographically Diverse Filtering Zones lists each set in full, with the priority numbers, for Email Gateway, Email Forwarding and Email Backup MX.
Older setups use mx2. or mx3. hostnames. Those records still work, so your mail keeps flowing. Move to the mx1. records above when it is convenient. Only the mx1. names have regional equivalents, so an mx2. setup cannot use single-region filtering.
Updating your firewall
If a firewall sits in front of your mail server, allow the addresses we deliver from:
- Both regions — allow the United States set and the European Union set.
- European Union only — allow the European Union set.
- United States only — allow the United States set.
If you choose a single region, we keep your mail in that region. We do not move it to the other region, so you do not need to allow the other region's addresses.
The current address lists are here: IP Addresses for Firewalls.