DocsReference
Connection values
Every hostname, address, port and header the setup guides refer to, in one place.
Updated August 29, 2026
Unique to your organization
These are issued when your organization is approved and shown on the portal's Setup page. They are not listed here.
| Value | Used in |
|---|---|
Relay address — <tenant>.smtp.rubysig.com |
Microsoft: outbound connector Routing and Security screens. Google: the mail route's host. |
DKIM record — rubysig1._domainkey.<your domain> TXT |
Your DNS provider. |
Your relay address identifies your organization to the relay. Treat it like a credential: it belongs in your admin console and nowhere else.
The same for every customer
| Value | Used in | |
|---|---|---|
| Relay hand-back address (IPv4) | 167.233.237.1 |
Microsoft: inbound connector. Google: SMTP relay service allow-list. Optionally your SPF record. |
| Relay hand-back address (IPv6) | 2a01:4f8:c015:909d::1 |
Google SMTP relay allow-list and SPF only. Microsoft's inbound connector accepts IPv4 only, and the relay always hands back over IPv4. |
| Relay port | 25 |
Every connector and route. |
| TLS | Required, publicly trusted certificate, subject name matches the relay address | Microsoft outbound connector Security screen; Google route options. |
| Loop-guard header | X-RubySig-Stamped: yes |
Microsoft transport rule exception; Google content compliance expression. |
| DKIM selector | rubysig1 |
The DNS record name, and what dkim=pass reports. |
| Relay hostname (HELO) | relay.rubysig.com |
What appears in Received: headers. |
Connector and rule names used in the guides
The names are yours to choose; these are the ones the screenshots use.
| Platform | Object | Name |
|---|---|---|
| Microsoft 365 | Outbound connector | RubySig Outbound |
| Microsoft 365 | Inbound connector | RubySig Inbound |
| Microsoft 365 | Transport rule | RubySig Stamp |
| Google Workspace | Mail route | RubySig relay endpoint |
| Google Workspace | Content compliance rule | Route unstamped outbound via RubySig relay |
| Google Workspace | SMTP relay rule | RubySig relay return path |
SMTP replies the relay gives
Listed with their meaning under Mail deferred or refused.