Hide the URL of my roundcube webmail in sent emails

[gracasola]

Hi!

I'm new at this forum, so I expect that it's the correct place to post my question.

I have installed roundcube in a common hosting, it connects to SMTP and IMAP of a mailserver of my hosting provider. But I noticed that if you sent an email from roundcube (e.g to gmail) in the headers it's posible to check the url of the roundcube installation. With other mail client, the "Received" header contains an other URL that doesn't match with the url that I use to do login. 

In other words, in the picture you can see the original email view of gmail, with a header "Received" that contains portico.xxxxxx.com that it's the url of my roundcube installation, whoever wants to do a DDoS or try credentials he can, and I want to know if there is some way to fix this in a easy way. I'm specially interested in hide the url, not the IP (xx.xx.83.49 in this case).

Thank you .

[SKaero]

The FQDN is from the mail server that sent the email, there isn't anything that can be changed in Roundcube to effect it.