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Install an Email Sender Seal in Roundcube webmail signature

Add the issued Email Sender Seal to the correct Roundcube sender identity as an HTML signature.

RC
Recommended methodEmail-signature linked image
Email-signature installation

Step-by-step instructions

  1. 1

    Open the correct identity

    In Roundcube open Settings, Identities and select the verified sender address. Each sender identity can have a different signature.

  2. 2

    Enable an HTML signature

    Check HTML signature so the formatting toolbar becomes available. Add the current seal image at approximately 300 by 106 pixels.

  3. 3

    Attach the certificate link

    Select the seal image and use the link control to set its destination to the VerifySeal public certificate URL. If the editor cannot link the image, add a linked Verify sender text line beneath it.

  4. 4

    Save and test externally

    Save the identity, compose an HTML message from that address and send it to an external mailbox. Confirm the image and certificate link survive delivery.

Open Roundcube sender identity documentation ↗
Email Sender Verification Seal

The signature image is only one part of verification

The sender domain must continue to publish a valid SPF record, the selected DKIM key and a DMARC policy. VerifySeal automatically rechecks these records according to the administrator schedule. For High Security messages, DKIM must cover the final Message-ID, VEM header and completed body.

  • SPF authorizes sending services
  • DKIM verifies the signed message domain
  • DMARC publishes the domain policy
Testing checklist

Confirm the installation is working

01

Visible

The complete 300 × 106 seal is visible in a received HTML message and is not cropped.

02

Clickable

The image opens the live VerifySeal sender certificate rather than an unlinked copied image.

03

Correct sender

The signature is assigned to the exact verified From address, not another identity or shared mailbox.

04

External test

A message received outside the organization retains the image, hyperlink and passing authentication results.

Platform notes
  • Roundcube versions and hosting configurations differ. The administrator can restrict HTML signature features.
All seal types

View every available VerifySeal design

Domain OwnershipEmail Sender VerificationHigh Security Email VerificationVerified BusinessVerified OrganizationVerified ResellerTrusted WebsiteCertified MemberAustralian Builder LicenceAustralian Financial Services LicenceWebsite PCI DSS ComplianceDocument IntegrityVerified Issuer DocumentHigh Security Document Authentication