Interactive Ssh blocked with Catalina

Since migrating to Catalina, I am not able to run an interactive shell through SSH to one of my linux servers. Using a Windows machine (I do not have a pre-Catalina machine available), I have no problem connecting.

Non-interactive ssh works correctly (I use an authorized key, so no password prompt) :

~> echo 'uname -a' | ssh user@server
Pseudo-terminal will not be allocated because stdin is not a terminal.
Linux ????? 4.9.78-xxxx-std-ipv6-64 #2 SMP Wed Jan 24 10:27:15 CET 2018 x86_64 GNU/Linux

Interactive ssh hangs, until the server's sshd kick me out :

~> ssh user@server
[Long wait]
packet_write_wait: Connection to ????: Broken pipe

When use verbose (-v), I can see that the authentication works:

~> ssh -v user@server
[...]
debug1: Authentication succeeded (publickey)
[...]
debug1: client_input_global_request: rtype [email protected] want_reply 0
debug1: Sending environment.
debug1: Sending env LC_CTYPE = UTF-8
[long Wait]
packet_write_wait: Connection to ????: Broken pipe

Not using a authorized key results in a password prompt, and then the same Broken pipe

Versions:

~> sw_vers
ProductName:    Mac OS X
ProductVersion: 10.15.1
BuildVersion:   19B88

~> ssh -V
OpenSSH_7.9p1, LibreSSL 2.7.3

Any idea ?

Solution 1:

After looking some more I found a workaround here and on superUser

Adding -o IPQoS=throughput to the ssh command line fixed my issue :

ssh -o IPQoS=throughput user@server

It's ugly to have to add this option, even if it could probably be added in ~/.ssh/config. It also probably hides some other issues. Any ideas?