FTP File upload to local server

RouterOS General
1

I have Mikrotik router (172.1.1.1) in my head office and there are several branches (172.1.0.0/16) connected to head office by pptp vpn. there is a ftp server in the head office (192.168.1.20) i Need to upload branch mikrotik router backup via VPN to the head office ftp server. by following command
/tool fetch address=172.1.1.1 src-path=$filename user=mtik mode=ftp password=mtik dst-path=/Backup/branchname.backup upload=yes port=2121;

then i have added NAT in my head office router as follows
add action=dst-nat chain=dstnat comment=“TEMP FTP” dst-port=2121 protocol=tcp
to-addresses=192.168.1.20 to-ports=21

But it is not working log shows
dstnat: in: out:(unknown 0), proto TCP (SYN), 172.1.3.1:54396->172.1.1.1:2121, len 60

Please help me to resolve this issue urgent

2

Besides port 21 you have to forward a range of (passive) ports to make FTP work.

If you get this to work you might want to consider upgrading your VPN connection to something newer?

3

Can you explain little bit. it is better if you can provide example

4

Sure:

FTP uses both port 21 and a passive port range (like 10000-20000 or whatever).
To make it work, you have to forward all ports involved (and not only port 21).

Check this article:
https://wiki.filezilla-project.org/Network_Configuration#Firewalls

Btw, what FTP server are you using?

Regarding VPN, PPTP is ancient and not safe. Get rid of it.