Re: hotmail can't deal with ECN

[David S. Miller]

CaT writes:
 > gozer:~# more /proc/sys/net/ipv4/tcp_ecn 
 > 1
 > 
 > and I can contact hotmail just fine.
 ...
 > where should I go to on hotmail to see it fail?

Try telnetting to port 25 on one of their
"*.hotmail.com" MX records.

For example:
? host -a hostmail.com
...
hostmail.com	651 IN	MX	10 mc6.law5.hotmail.com
...
mc6.law5.hotmail.com	383 IN	A	216.33.238.136
? telnet 216.33.238.136 25
Trying 216.33.238.136...
telnet: Unable to connect to remote host: Connection refused
?

Some of the MX records that show up for hotmail.com go
to different machines, such as INKY.SOLINUS.COM which seems
to let ECN connections through just fine.

Later,
David S. Miller
[e-mail]