NowSMS and SSL Certificate Chains

Posted by on Mar 8, 2011 in Support Blog

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If you have purchased an SSL certificate from a certificate authority for use on a NowSMS server, you may encounter a problem with some browsers displaying a warning or refusing to accept the certificate.  This can occur when SSL certificates are not signed by a certificate authorities’ root certificate, but by an intermediate certificate.  (This has been observed with certificates issued by GoDaddy, see

When a certificate is issued by a certificate authority by an intermediate certificate, it is necessary to install not just your certificate on the server, but additionally it is necessary to install the certificate chain for the CA’s intermediate certificate.  This certificate chain will be provided by the certificate authority along with your signed certificate.

At this time, an updated version of SMSSSL.DLL is required to support an SSL certificate chain.  An update can be downloaded at  To install the update, stop the NowSMS services and exit the NowSMS program.  Next, update the SMSSSL.DLL file in Program Files (or Program Files (x86)) \ NowSMS with the version in this ZIP file.

Locate the directory that contains your SSL certificate request (SSL.CSR).  This is either the ProgramData\NowSMS directory (Windows 7/Vista/2008) or Program Files\NowSMS (XP/2003) directory.

Using a text editor, such as NOTEPAD.EXE, create or edit a file named SSL.CA, which is the filename designated to contain your signed SSL certificate.  Your signed certificate should be placed at the start of this file, including the —–BEGIN CERTIFICATE—– and —–END CERTIFICATE—– markers.  Following  your signed certificate, you should include any intermediate certificates in this same text file.  If there are multiple intermediate certificates, they should be ordered in the path from your server certificate toward the root CA certificate.

The NowSMS service must be restarted after updating an SSL certificate file in order for the new certificate to take effect.

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2 Responses to “NowSMS and SSL Certificate Chains”

  1. Arumugam says:

    Please Tell us , how to use our SMS modem with Vb 6.0 Based software. If we want to buy License , pls send the details