Apache Virtual Hosts on different domain names AND ports - apache

Question

I use a Ubuntu 16.04 server VM on which I have to configure the following domains:
maindomain.com:80
otherport.com:8080
Each domain pointing to the VM's IP, but to a different directory obviously.
I managed to get bind9 to make these domains point to the VM's IP when the VM is the DNS server, and I configured Apache to get the following results:
Good:
maindomain.com:80 returns maindomain's index
otherport.com:8080 returns otherport's index
Bad:
maindomain.com:8080 returns otherport's index
otherport.com:80 returns maindomain's index
If I put both on port 80, each is separated, but if I do different ports it seems that Apache just cares about the port.
How could I block the access to maindomain.com:8080 and otherport.com:80?
maindomain.com.conf file:
<VirtualHost maindomain.com:80>
ServerAdmin webmaster#localhost
ServerName maindomain.com
ServerAlias www.maindomain.com maindomain.com
DocumentRoot "/var/www/html/maindomain"
<Directory /var/www/html/maindomain>
Require all granted
</Directory>
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>
otherport.com.conf file:
<VirtualHost otherport.com:80>
ServerAdmin webmaster#localhost
ServerName otherport.com
ServerAlias www.otherport.com otherport.com
DocumentRoot "/var/www/html/otherport"
<Directory /var/www/html/otherport>
Require all granted
</Directory>
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

Answer 1

I managed to get it done, but I think it's more of a dirty hack than an actual solution. I made two more virtual hosts like so :
maindomain.com.trap.conf
<VirtualHost *:8080>
ServerAdmin webmaster#localhost
ServerName maindomain.com
ServerAlias www.maindomain.com maindomain.com
DocumentRoot "/var/www/html/maindomain"
<Directory /var/www/html/maindomain>
Require all denied
</Directory>
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>
The other one having the names and port switched.
By the way, I left <VirtualHost *:80> and <VirtualHost *:8080> in the first two .conf files I mentioned in my first post.