Cannot connect using FTP with AT&T Hotspot

[Nick N. Kanaya]

I can connect to my FTP site with no problem whenever I am using a Verizon Hotspot (MiFi7730L) using FileZilla, however, when I tried to use an AT&T Hotspot (Unite Explorer AC815S) the connection always times out at 20 seconds and I am unable to connect. Can you advise as to why this happens and is there a solution to this problem? It is annoying to have to switch my hotspot settings every time I have to use FileZilla. Please advise. Thank you.

FileZilla Client

---

Version: 3.25.2

Build information:

Compiled for: x86_64-w64-mingw32
Compiled on: x86_64-unknown-linux-gnu
Build date: 2017-04-30
Compiled with: x86_64-w64-mingw32-gcc (GCC) 4.9.1
Compiler flags: -g -O2 -Wall -std=gnu++14

Linked against:

wxWidgets: 3.0.3
SQLite: 3.18.0
GnuTLS: 3.5.8

Operating system:

Name: Windows 7 (build 7601, Service Pack 1), 64-bit edition
Version: 6.1
Platform: 64-bit system
CPU features: sse sse2 sse3 ssse3 sse4.1 sse4.2 avx pclmulqdq
Settings dir: C:\Users\Nickjr\AppData\Roaming\FileZilla\

[Tim Kosse]

What is being written to the message log?

[Nick N. Kanaya]

This is what I get and it won't connect to the server. This happens with the AT&T hotspot only.

Status: Resolving address of ftp.nickkanaya.net
Status: Connecting to 67.195.61.88:21...
Status: Connection established, waiting for welcome message...
Status: Initializing TLS...
Error: Connection timed out after 20 seconds of inactivity
Error: Could not connect to server
Status: Waiting to retry...
Status: Resolving address of ftp.nickkanaya.net
Status: Connecting to 67.195.61.88:21...
Status: Connection established, waiting for welcome message...
Response: 220-Welcome to the Yahoo! Web Hosting FTP server
Response: 220-Need help? Get all details at:
Response: 220-​http://help.luminate.com/help/us/webhosting/gftp/
Response: 220-
Response: 220-No anonymous logins accepted.
Response: 220-Yahoo!
Response: 220-Local time is now 09:33. Server port: 21.
Response: 220-This is a private system - No anonymous login
Response: 220 You will be disconnected after 5 minutes of inactivity.
Command: AUTH TLS
Response: 234 AUTH TLS OK.
Status: Initializing TLS...
Error: Connection timed out after 20 seconds of inactivity
Error: Could not connect to server

[Tim Kosse]

Ah, the sad symptoms. Unfortunately AT&T is still actively sabotaging FTP traffic, there's nothing I can do. You need to contact AT&T and demand that they stop inspecting and modifying any traffic above OSI layer 3.