Error "IPv6-only host" - what does it mean?

[dare2go]

After having been through several changes at once (website moved to new server and new laptop for me) I can't get Filezilla to work!

Every time I connect to my web server I get in, but it stalls before the directory listing (and finally aborts the connection).

When I run the "Settings Wizard" of Filezilla I receive the error

You appear to be using an IPv6-only host. This wizard does not support this environment.
Connection closed

I tried to google IPv6 host, but all I find is tech gobbledygook I don't understand...

What does it mean: You appear to be using an IPv6-only host?

Situation:
1. I have added Filezilla to the Windows Firefall as an excluded program. Filezilla Version 3.66.0
2. The only internet connection I have access to, is a hotspot via my mobile phone!
(I don't have a broadband connection or access to one!)
3. I did search the forum for "IPv6 host" but all I find is a really long thread, pages long, about update problems - with no clear answer to IPv6.

Can somebody please help me to solve this connection problem?
(and please consider, whilst not completely "computer illiterate", I am very close to 69 years old and not fluent in tech talk.)

[boco]

Internet host names (or URLs) are essentially just human-readable aliases, made for convenience. Actually, every peer in the Internet (servers and clients, too) is addressed by something called IP address.
There are two kinds (or better, versions) of IP addresses, the older IPv4 and the modern IPv6. Every Internet peer gets assigned at least one of these.

IPv4 addresses look like "192.0.20.1", four octets in decimal notion, usually.
IPv6 addresses appear like "2001:db8:23:5::4b:c", 16 octets (or less in shorted form), in groups of two, hexadecimal notion.


Now, you do get assigned your IPs by your Internet provider. In most cases, this will be an IPv4 address or both an IPv4 and IPv6 address. However, due to the shortage of IPv4 addresses, your provider might have assigned only an IPv6 address to your device (together with an IP translation service like DS-Lite so you can reach the whole Internet). Having only an IPv6 means your device is an IPv6-only host, it can not be reached by anything not supporting IPv6. The wizard does not seem to support this constellation so far.

However, the Wizard being unavailable doesn't have anything to do with your problem. Please post a complete log of a failed connection attempt, from start to finish.

[dare2go]

This is the entire log of the "wizard", using the pre-set entries:

Connecting to probe.filezilla-project.org
Connection established, waiting for welcome message.
Response: 220 FZ router and firewall tester ready
USER FileZilla
Response: 331 Give any password.
PASS 3.66.0
Response: 230 logged on.
Checking for correct external IP address
You appear to be using an IPv6-only host. This wizard does not support this environment.
Connection closed

PLEASE NOTE once more: I am using a MOBILE HOTSPOT, not a router with fixed line internet! My Filezilla works on WiFi, but I don't have access to it.

I've tried to play with the pre-set entries and changed them - whichever combination I've tried so far, it always stalls/aborts just before receiving data.
(Unfortunately the Filezilla "help" files aren't anything I really comprehend! It would be nice if they would be written in 'layman's terms' or would give at least links to more detailed explanation of some of the terms used... eg: what is a NAT router? With a Mobile Hotspot I'm pretty sure there's NO router involved at my end. It's also a "bad joke" that the "help" files end with instructions for Windows 8, where for about 2 years we're up to Windows 11, with 10 nearly past use-by-date.)

[boco]

We wanted a log of an actual connection attempt to the server. NOT from the Wizard, we all know and agree now that it doesn't work.

My suspicion would be that the server is IPv4, and the translation service from the mobile provider messes up.

[dare2go]

Oh, great, 24 hour wait... for -?-

Here is a screen capture, some IDs (like IP address) blanked out.


I could have uploaded this yesterday, as it has been sitting on my hd for over 24 hours. But the question wasn't clear [to me].

[boco]

No, the server supports IPv6 ("Connecting to [2001:...]:21".

Could you test the server using our special test site https://ftptest.net? That's to rule out a server error, you wouldn't believe how frequently they are mis-configured...

[dare2go]

Here's the log - and it again starts with an error about IPv6!

Warning: The entered address does not resolve to an IPv6 address.

Status: Connected, waiting for welcome message...

Reply: 220---------- Welcome to Pure-FTPd [privsep] [TLS] ----------

Reply: 220-You are user number 1 of 50 allowed.

Reply: 220-Local time is now 19:34. Server port: 21.

Reply: 220-This is a private system - No anonymous login

Reply: 220-IPv6 connections are also welcome on this server.

Reply: 220 You will be disconnected after 15 minutes of inactivity.

Command: CLNT https://ftptest.net on behalf of 2001:8004:44106c4c:7f8f:769e:7f9a

Reply: 530 You aren't logged in

Command: AUTH TLS

Reply: 234 AUTH TLS OK.

Status: Performing TLS handshake...

Status: TLS handshake successful, verifying certificate...

Status: Received 3 certificates from server.

Status: cert[0]: subject='CN=node615.namehero.net' issuer='C=US,ST=TX,L=Houston,O=cPanel\5c, Inc.,CN=cPanel\5c, Inc. Certification Authority'

Status: cert[1]: subject='C=US,ST=TX,L=Houston,O=cPanel\5c, Inc.,CN=cPanel\5c, Inc. Certification Authority' issuer='C=GB,ST=Greater Manchester,L=Salford,O=COMODO CA Limited,CN=COMODO RSA Certification Authority'

Status: cert[2]: subject='C=GB,ST=Greater Manchester,L=Salford,O=COMODO CA Limited,CN=COMODO RSA Certification Authority' issuer='C=GB,ST=Greater Manchester,L=Salford,O=Comodo CA Limited,CN=AAA Certificate Services'

Command: USER dare2go

Reply: 331 User dare2go OK. Password required

Command: PASS ********

Reply: 230 OK. Current restricted directory is /

Command: SYST

Reply: 215 UNIX Type: L8

Command: FEAT

Reply: 211-Extensions supported:

Reply: UTF8

Reply: EPRT

Reply: IDLE

Reply: MDTM

Reply: SIZE

Reply: MFMT

Reply: REST STREAM

Reply: MLST type*;size*;sizd*;modify*;UNIX.mode*;UNIX.uid*;UNIX.gid*;unique*;

Reply: MLSD

Reply: PRET

Reply: AUTH TLS

Reply: PBSZ

Reply: PROT

Reply: TVFS

Reply: ESTA

Reply: PASV

Reply: EPSV

Reply: 211 End.

Command: PBSZ 0

Reply: 200 PBSZ=0

Command: PROT P

Reply: 200 Data protection level set to "private"

Command: PWD

Reply: 257 "/" is your current location

Status: Current path is /

Command: TYPE I

Reply: 200 TYPE is now 8-bit binary

Command: PASV

Reply: 227 Entering Passive Mode (198,175,150,252,234,34)

Command: MLSD

Error: Connection timed out

[edited to add]

The warning at the bottom is exactly highlighting my problem - again:

Error: Connection timed out

Timeouts are usually caused by some router and/or firewall that is interrupting the connection.
Try uninstalling all firewalls and plug your computer directly into your modem, thus bypassing the router.

I wouldn't know how to uninstall (and then re-install) the Windows 10 Firewall. But I explicitly allowed FileZilla to pass thorough the firewall.

[botg]

If https://ftptest.net/ fails the issue is with the server or a server-side firewall or NAT router. You need to contact your server administrator or server hosting provider for further assistance.