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Troubleshooting When Using MobaXterm SSH

language
eng
date
Nov 6, 2025
slug
Error0_mobaxterm
author
status
Public
tags
mobaxterm
ssh
summary
Information about the /etc/ssh_config line 1: Missing argument error that occurs when using SSH in MobaXterm.
type
Post
thumbnail
์Šคํฌ๋ฆฐ์ƒท 2025-11-06 083722.png
category
๐ŸžTroubleShooting
updatedAt
Jun 10, 2026 03:35 PM
Iโ€™ve been using MobaXterm to conveniently develop on other devices via SSH. Since it supports SFTP and even X11 display forwarding, my workflow has been to use MobaXterm for simple operations and checks, and switch to VS Code when I need to write actual code. This setup has been the best fit for my usage pattern.
But one day, when I tried to SSH from my main laptop, I kept getting an error. Searching online didnโ€™t give me any useful answers, so I dug into it myself.
notion image
Taking the error message literally, I opened the /etc/ssh_config file using vi, and noticed that the username field was empty. That empty field was what caused the issue.
notion image
If you enter an appropriate username in the User field, SSH works again. The problem, however, is that you need to re-enter the username every time you restart MobaXterm. After some digging, I found that you can fix this by going to Settings โ†’ Configuration โ†’ SSH tab, and filling in Default login with your username.
notion image
If you use MobaXterm frequently, itโ€™s worth remembering this (I keep forgetting it myselfโ€ฆ).

X11 authority error

when using GUI on mobaXterm, you have to use X11. If you try to use it without preparation, youโ€™ll run into permission issues. In that case, you need to configure the XAUTHORITY-related settings as follows before using it.
sudo env DISPLAY=$DISPLAY XAUTHORITY=$HOME/.Xauthority #and add command.
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