NoMoshServerArgs error with mosh-server 1.4.0 on Ubuntu 24 - mosh1 works fine

[carstenf]

Issue Description

The mosh command fails with NoMoshServerArgs error, while mosh1 connects successfully to the same server with identical configuration.

Error Message:

NoMoshServerArgs - Did not find mosh server startup message. (Have you installed mosh on your server?)
Use mosh1 for the deprecated (previous) mosh version.

Configuration

• Blink Version: Latest from App Store (December 2025)
• iOS/iPadOS Version: 18.x
• Server: Ubuntu 24.04 LTS (128.140.104.236)
• mosh-server Version: 1.4.0-1ubuntu3

Server Configuration

• mosh-server location: /usr/bin/mosh-server
• Explicitly configured in Blink host settings
• Ports configured: 60000:61000
• PATH in .bash_profile: /usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin
• SSH works perfectly
• Firewall allows UDP 60000-61000

Server Verification

Manual test confirms mosh-server works correctly:

$ mosh-server new -s -c 256 -l LANG=en_US.UTF-8
Warning: SSH_CONNECTION not found; binding to any interface.
MOSH CONNECT 60003 UltFYKvvbl2tE3CPCPNdpw

mosh-server (mosh 1.4.0) [build mosh 1.4.0]
Copyright 2012 Keith Winstein <mosh-devel@mit.edu>

Blink Host Config

Alias: Python1-carsten
HostName: 128.140.104.236
Port: 22
User: carsten
Mosh Server: /usr/bin/mosh-server
Mosh Port: 60000:61000

Expected vs Actual Behavior

Expected: mosh Python1-carsten connects successfully

Actual:

• ❌ mosh Python1-carsten → NoMoshServerArgs error
• ✅ mosh1 Python1-carsten → Works perfectly
• ✅ ssh Python1-carsten → Works perfectly

Timeline

• Early December 2025: mosh worked fine
• December 12, 2025: mosh fails, mosh1 still works
• No server configuration changes
• Possible Blink app update caused the regression

Additional Context

This appears related to #2002 from April 2024, but the problem persists in December 2025. The issue seems to be that Blink's newer mosh implementation doesn't properly recognize the startup message from mosh-server 1.4.0, while the legacy mosh1 command works flawlessly.

Checklist

• Using latest version on the App Store
• Read the docs
• Searched for existing GitHub issues