Appendix I: Additional PX3TS Information788Illustration - GMAIL SMTP Certificate ChainIf you will apply your company's SMTP service to PX3TS, ignore thisGMAIL illustration topic. Simply contact your IT department to retrievethe appropriate certificate (chain) file and upload it to the PX3TS.This section illustrates the upload of a TLS "root" certificate for using the"gmail.com" SMTP service.Unlike normal TLS websites, where you can easily find its servercertificate by using a Web browser, the method to find an SMTP server'scertificate is more difficult, which requires appropriate tools andsufficient technical knowledge. For example, you may have to use theopenssl command as illustrated below to retrieve the certificate of theGMAIL SMTP server.Step 1 -- Find the certificate(s) the SMTP server has:1. Issue the following command in the appropriate command lineapplication. In the following example command, we assume the server"smtp.gmail.com" provides the SMTP service. You can changethe server name, port number, command or even the tool asneeded.openssl s_client -showcerts -connect smtp.gmail.com:465Alternative: To view the certificate chain instead of all certificates,you can remove the "-showcerts" option from the above command.2. Information that shows the certificates the SMTP server has isdisplayed....Certificate chain0 s:/C=US/ST=California/L=Mountain View/O=Google Inc/CN=smtp.gmail.comi:/C=US/O=Google Inc/CN=Google Internet Authority G2-----BEGIN CERTIFICATE-----MIIEdjCCA16gAwIBAgIIbzO9vIL2OXcwDQYJKoZIhvcNAQELBQAwSTELMAkGA1UE..YHKKJH96sSNC+6dLpOOoRritL5z+jn2WFLcQkL2mRoWQi6pYTzPyXB4D-----END CERTIFICATE-----1 s:/C=US/O=Google Inc/CN=Google Internet Authority G2i:/C=US/O=GeoTrust Inc./CN=GeoTrust Global CA
