Hi,

  I am having big problems install new software and upgrading my current F22 using DNF.
  Maybe I am wrong but I think that if I could force dnf to use http(s) instead of ftp, then my
problems would be solved.

  Please advise.

Here is one example. 

$ sudo dnf install AcetoneISO
Last metadata expiration check performed 0:48:31 ago on Mon Jun 29 12:15:05 2015.
Dependencies resolved.
================================================================================
 Package            Arch           Version                 Repository      Size
================================================================================
Installing:
 AcetoneISO         x86_64         6.7-14.fc22             fedora         301 k
 ftplib             x86_64         3.1-13.fc22             fedora          22 k
 xbiso              x86_64         0.6.1-12.fc22           fedora          23 k

Transaction Summary
================================================================================
Install  3 Packages

Total download size: 347 k
Installed size: 718 k
Is this ok [y/N]: y
Downloading Packages:
[MIRROR] AcetoneISO-6.7-14.fc22.x86_64.rpm: Curl error (28): Timeout was reached for ftp://mirror.easyspeedy.com/fedora/releases/22/Everything/x86_64/os/Packages/a/AcetoneISO-6.7-14.fc22.x86_64.rpm [Connection time-out]
[MIRROR] xbiso-0.6.1-12.fc22.x86_64.rpm: Curl error (28): Timeout was reached for ftp://mirror.easyspeedy.com/fedora/releases/22/Everything/x86_64/os/Packages/x/xbiso-0.6.1-12.fc22.x86_64.rpm [Connection time-out]
[MIRROR] ftplib-3.1-13.fc22.x86_64.rpm: Curl error (28): Timeout was reached for ftp://mirror.easyspeedy.com/fedora/releases/22/Everything/x86_64/os/Packages/f/ftplib-3.1-13.fc22.x86_64.rpm [Connection time-out]
[MIRROR] AcetoneISO-6.7-14.fc22.x86_64.rpm: Curl error (28): Timeout was reached for ftp://ftp.otenet.gr/pub/linux/fedora/linux/releases/22/Everything/x86_64/os/Packages/a/AcetoneISO-6.7-14.fc22.x86_64.rpm [Connection time-out]
[MIRROR] ftplib-3.1-13.fc22.x86_64.rpm: Curl error (28): Timeout was reached for ftp://ftp.otenet.gr/pub/linux/fedora/linux/releases/22/Everything/x86_64/os/Packages/f/ftplib-3.1-13.fc22.x86_64.rpm [Connection time-out]
[MIRROR] xbiso-0.6.1-12.fc22.x86_64.rpm: Curl error (28): Timeout was reached for ftp://ftp.otenet.gr/pub/linux/fedora/linux/releases/22/Everything/x86_64/os/Packages/x/xbiso-0.6.1-12.fc22.x86_64.rpm [Connection time-out]
(1/3): ftplib-3.1-13.fc22.x86_64.rpm             95  B/s |  22 kB     04:00    
(2/3): xbiso-0.6.1-12.fc22.x86_64.rpm            99  B/s |  23 kB     04:00    
(3/3): AcetoneISO-6.7-14.fc22.x86_64.rpm        1.3 kB/s | 301 kB     04:00    
--------------------------------------------------------------------------------
Total                                           1.4 kB/s | 347 kB     04:04     
Running transaction check
Transaction check succeeded.
Running transaction test