Is it possible to configure zimbr (y) with busy ports - 25; 443; 80 on a single IP?

Question

ubuntu

tell me if it is possible to somehow configure the zimbra mail server in such conditions
there is a dedicated ip on it a corporate website is running (on port 80) with a domain like _domaim.com.ua_, the site is hosted on our server this server is a gateway + (squid + mail ( old) port 25 is busy) + there is WIN2003 with DNS and AD which is located behind the firewall with the entire local network (dfl-800 on port 443 is temporarily (permanently) used for port forwarding) access to the domain registrar panel is not yet available,
which comes out: 25th the port is occupied by old mail, port 443 is occupied by DFL-800, on the 80th site.
what would you like to set up: so that users on the local network, as well as branches (outside the local network) in the browser drive in one address and get into the mail with all its
capabilities
since it is not possible to add mail to the domain (domaim.com.ua_) reguled the new domen.dd.ua in its settings, registered the IP of the company in the A record, added a new regnet domain of the form mail.domen.dd.ua to the MX record by
setting up zimbr ( s) I can get into the LAN in the web interface and I can even send and receive mail in the LAN, I can also send mail to the Internet, but I can’t get it back, I also can’t reach the web from the Internet, although I can’t access the admin panel with port 7071 open from the Internet is obtained.
Ports 80,443,7071,8080 are forwarded.
win 2003 is used as a local DHCP, DNS, AD, for win users
, the main Internet comes to DFL and a backup link from it to the local network, it (DFL) is used to forward terminal ports, 80, 443, 25 and others.
the gateway in the local network has two interfaces, one in the other in the DFL on the gateway, squid, mail (old), the site through it, users go to no.
zimbra stands on a separate server in the local network (has an IP local network) behind DFL, but for it ip is forwarded on the gateway and therefore it goes past the squid to no.
So is it possible to configure zimbr (y) as I described above without disabling old mail on port 25 and without disabling the hardware (DFL-800) from remote access by disabling port 443