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Author Topic: D-Link DSL 6850u firewall blocking FTP clients on Passive Mode.  (Read 2845 times)


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I just received D-Link DSL 6850u router.
I have sites that I always connected  to via Filezilla FTP - using unencrypted FTP and Passive mode. Since I changed to D-Link router these connections have stopped working. SFTP works and I think active mode works. I have tried on multiple FTP clients(WinSCP,CoreFTP) and all have same problem. FTP makes the connection, enters passive mode, and gets stuck after sending MLSD command - Timeout. No information is coming from server. I have tried same sites from other routers and they WORK.
Finally, after spending hours on this, I discovered under Setup -> WAN SETTINGS -- PPPOE WAN (Where my ISP username and password is entered), there is checkbox for firewall. IF I DISABLE FIREWALL, EVERYTHING WORKS.
1) Is this safe - or will I now open up all ports to hackers?
2) Which rules do I  need to add to allow me to connect to sites via FTP?
« Last Edit: April 23, 2015, 05:55:42 AM by neyl »


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Re: D-Link DSL 6850u firewall blocking FTP clients on Passive Mode.
« Reply #1 on: April 23, 2015, 11:02:18 AM »


  • What Hardware version is your modem? Look at the sticker under modem.
  • Link>What Firmware version is currently loaded? Found on the modems web page under status.
  • What region are you located?

I would presume that what ever FTP ports you are using, you may need to use any available firewall rules to add some exception rules for your FTP configurations to work when the Firewall feature is enabled. It's recommended to keep the firewall feature enabled. Review the user manual for setting up firewall rules. If there isnt' a specific option to set up rules, see if this model modem had either Virtual Serer or Port Forwarding configurations to set up some rules for FTP.

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