Question

I've been using a python script to download files from a device using another router but after installing the Teltonika router RUT955 it stops working. I just installed the latest firmware but it hasn't resolved the problem. I'm using the python library "ftplib". What can I do to solve this problem?

Answer 1

Hello,

Could you login to your device via CLI or SSH, execute the following commands and see if that helps:

echo "net.netfilter.nf_conntrack_helper=1" >> /etc/sysctl.d/11-nf-conntrack.conf

and

/etc/init.d/sysctl restart

Best regards,

Comments

What does this CLI command do?

---

The idea behind the commands is that some protocols, such as FTP, have a well known port 21 to request data from the server, but it can use any port between 1024 and 65535 for data reception. This creates two independent, but related, connections, yet the firewall is unable to associate them and filter properly, thus, likely dropping packets from server. That is what I assume is the issue. Helper, which is enabled by the commands above, enables a mechanism, which relates these connections and creates an exception in the firewall to accept them.

Have you tried it and did it help?    

Best regards,

---

Dear Zygimantas,

it works! Thank you very much for your quick and useful answer.

Best regards,