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D-Link VPN Router => DSR-250 => Topic started by: Cyberg on February 11, 2018, 09:30:57 PM

Title: Cannot connect to FTP internet sites
Post by: Cyberg on February 11, 2018, 09:30:57 PM
I don't know if this is a router problem.  When I try to access an internet FTP site, for example: ftp://ftp2.dlink.com to download drivers/firmware all of the browsers I had tried (Edge/Chrome/IE) fail to connect.  All HTTP an HTTPS links work fine.  This occurs on a Windows 10 desktop and Windows 10 laptop.  To test accessing an FTP server on my local house network I created an FTP server on my FreeBSD system.  I was able to connect to it from my Win10PC using ftp.exe as well as ftp://<ip address>.  Since this proves it is not the browser then it could be the Windows firewall.  The simplest test here is to turn off the Windows firewall.  I did this and tried accessing any ftp site (i.e. ftp://whateverNameOrAddress) and it still fails.  My question is, could the router be filtering TCP or FTP in a way that causes this problem?  I tried nearly all the DSR-250 settings I could think of.  Any help would be greatly appreciated.
Title: Re: Cannot connect to FTP internet sites
Post by: GreenBay42 on February 13, 2018, 07:41:40 AM
Does this happen only when using a browser?

Have you tried using a FTP client such as Filezilla?  Try this and look at the logs when trying to connect.

By default the router should not be blocking, especially since you are initiating the request locally.

Is the DSR-250 connected to a modem or modem/router? (double-NAT)

Title: Re: Cannot connect to FTP internet sites
Post by: FurryNutz on February 13, 2018, 09:42:45 AM
Link>Welcome! (http://forums.dlink.com/index.php?topic=48135.0)



Internet Service Provider and Modem Configurations

Quote from: Cyberg on February 11, 2018, 09:30:57 PM
I don't know if this is a router problem.  When I try to access an internet FTP site, for example: ftp://ftp2.dlink.com to download drivers/firmware all of the browsers I had tried (Edge/Chrome/IE) fail to connect.  All HTTP an HTTPS links work fine.  This occurs on a Windows 10 desktop and Windows 10 laptop.  To test accessing an FTP server on my local house network I created an FTP server on my FreeBSD system.  I was able to connect to it from my Win10PC using ftp.exe as well as ftp://<ip address>.  Since this proves it is not the browser then it could be the Windows firewall.  The simplest test here is to turn off the Windows firewall.  I did this and tried accessing any ftp site (i.e. ftp://whateverNameOrAddress) and it still fails.  My question is, could the router be filtering TCP or FTP in a way that causes this problem?  I tried nearly all the DSR-250 settings I could think of.  Any help would be greatly appreciated.
Title: Re: Cannot connect to FTP internet sites
Post by: Cyberg on February 15, 2018, 08:08:27 PM
Quote from: GreenBay42 on February 13, 2018, 07:41:40 AM
By default the router should not be blocking, especially since you are initiating the request locally.

Is the DSR-250 connected to a modem or modem/router? (double-NAT)

Well the router is obviously not blocking FTP for the LAN since both my FreeBSD machine and my Win10 PC are wired to the router and I could connect to the FTP server on my FreeBSD machine.  The DSR-250 is connected to a cable modem.
Title: Re: Cannot connect to FTP internet sites
Post by: Cyberg on February 15, 2018, 08:22:22 PM
Quote from: FurryNutz on February 13, 2018, 09:42:45 AM
Link>Welcome! (http://forums.dlink.com/index.php?topic=48135.0)

  • What Hardware version is your router? Look at sticker under the router case.
  • Link>What Firmware (http://forums.dlink.com/index.php?topic=47512.0) version is currently loaded? Found on the routers web page under status.
  • What region are you located?
  • Are you wired or wireless connected to the router?

Internet Service Provider and Modem Configurations
  • What ISP Service do you have? Cable or DSL?
  • What ISP Modem Mfr. and model # do you have?

Quote from: Cyberg on February 11, 2018, 09:30:57 PM
I don't know if this is a router problem.  When I try to access an internet FTP site, for example: ftp://ftp2.dlink.com to download drivers/firmware all of the browsers I had tried (Edge/Chrome/IE) fail to connect.  All HTTP an HTTPS links work fine.  This occurs on a Windows 10 desktop and Windows 10 laptop.  To test accessing an FTP server on my local house network I created an FTP server on my FreeBSD system.  I was able to connect to it from my Win10PC using ftp.exe as well as ftp://<ip address>.  Since this proves it is not the browser then it could be the Windows firewall.  The simplest test here is to turn off the Windows firewall.  I did this and tried accessing any ftp site (i.e. ftp://whateverNameOrAddress) and it still fails.  My question is, could the router be filtering TCP or FTP in a way that causes this problem?  I tried nearly all the DSR-250 settings I could think of.  Any help would be greatly appreciated.

Title: Re: Cannot connect to FTP internet sites
Post by: FurryNutz on February 16, 2018, 11:43:20 AM
Do you see any logging in the router when you try to access an FTP site on the WAN side?
Title: Re: Cannot connect to FTP internet sites
Post by: Cyberg on February 16, 2018, 09:34:30 PM
I do see logging concerning FTP when I attempt to connect using a browser (i.e. ftp://ftp2.dlink.com).  As an experiment, I opened a command prompt and entered "ftp ftp2.dlink.com" and I was connected and prompted to logon.  I tried username "anonymous" and the result was "Connection closed by remote host".

Interestingly, the browser and command prompt attempts both result in the same type of entries in the router log under category Firewall (see below).  The difference is the browser doesn't provide any detail about attempting to log on anonymously.  The browser just displays the generic message: "This site can't be reached.  The connection was reset."  Below is an example router log entry showing the failed FTP anonymous login attempt.

FIREWALL        Alert        [Fri Feb 16 22:58:34 2018(GMT-0600)] [DSR-250] [3.11B101H] [Firewall] [Alert] [IPS] [*DROP*[1:553:7] POLICY FTP anonymous login attempt [Classification: Misc activity] [Priority: 3]: {TCP} <MyRouterIpAddress>:49837 -> 54.187.190.227:21]
Title: Re: Cannot connect to FTP internet sites
Post by: FurryNutz on February 17, 2018, 11:12:44 AM
What kind of firewall rules do you have set?

Do different browser's experience the same issue?

I don't get a log in window for D-Links FTP site here.

Title: Re: Cannot connect to FTP internet sites
Post by: Cyberg on February 20, 2018, 09:39:06 AM
I don't have any firewall rules set.  The default setting is no rules defined.

I tried MS Edge and IE in Windows 10.  Same type of error.

I was talking to a couple friends who work in IT.  They suggested to bypass the router and use a wired connection from my PC or laptop directly to the cable modem.  If it works, then the ftp problem is in the router.  Also if bypassing the router works, they then suggested to work around the FTP problem by putting a switch between the router and cable modem.  That way whenever I need to use FTP I can temporarily move my wired connection to the switch.
Title: Re: Cannot connect to FTP internet sites
Post by: FurryNutz on February 20, 2018, 10:00:22 AM
I would contact D-Link support if you find that the router is the problem. You don't need a switch in front of the router as the router should be able to process any FTP sites. All D-Link home class routers I've used and tested work. I presume these business class do the same, however could be either a configuration issue or FW issue that D-Link should be able to help with.
Title: Re: Cannot connect to FTP internet sites
Post by: Cyberg on February 20, 2018, 09:18:00 PM
I figured out the cause of the problem without having to bypass the router.  I was testing the ftp connection again and looking at the router log.  The keywords in the log that stuck out this time were:

[Firewall] [Alert] [IPS]

More specifically the letters "IPS" (Intrusion Protection System).  I had just recently been through all the settings again and I recalled seeing this feature.  In my router there are 3 buttons:

Enable Intrusion Detection
Enable Intrusion Prevention
IPS/IDS Checks Active Between LAN and WAN

All of the buttons were turned ON.  I turned all of them OFF and ran the test again.  This time I was able to:

1) Anonymous logon to the ftp URL from the command line
2) Download the driver from the FTP site

After the download succeeded I turned them all back ON.  I would like to mention that discovering this is not at all intuitive and there is no documentation mentioning anything about this.  I don't see how Intrusion Detection/Prevention applies to anonymous FTP.  Anonymous FTP should not be listed as a malicious attack signature.  On this Firewall > IPS page shows under IPS Status > Number of signatures loaded:  501
Title: Re: Cannot connect to FTP internet sites (RESOLVED)
Post by: FurryNutz on February 21, 2018, 08:36:10 AM
Glad you were able to figure this out.

Thanks for pointing future users to the solution. I'll keep this in mind.  ;)

Enjoy.  ;)
Title: Re: Cannot connect to FTP internet sites
Post by: Cyberg on February 21, 2018, 09:38:34 AM
Thank you for putting up with my frustration and answering my questions.  I hope this helps other users.

I have a couple other router questions that are not FTP related.  I think I will create another thread for them.
Title: Re: Cannot connect to FTP internet sites
Post by: FurryNutz on February 21, 2018, 10:30:18 AM
 ;)