Re: T/TCP: Syn and RST Cookies

Matti Aarnio (matti.aarnio@tele.fi)
Mon, 13 Apr 1998 00:56:27 +0300 (EEST)

> Date: Sun, 12 Apr 1998 01:44:27 -0700
> From: "David S. Miller" <davem@dm.cobaltmicro.com>
> Date: Sat, 11 Apr 1998 18:16:19 -0700
> From: Jim Dennis <jimd@starshine.org>
....
> Is T/TCP (RFC1644) implemented in the Linux kernel?
>
> No, and until it is at least a real RFC standard, it won't be.

It is not implemented per se, but there exists support for
receiving data (Push) with connection startup SYN packet.

This means that lattest 2.1.* kernels will do something sensible
with incoming T/TCP packet. It does not mean there exists
T/TCP support. Especially it does NOT mean that there exists
user-space support for T/TCP per RFC 1644, or its FreeBSD
implementation thereof.

Systems that don't support T/TCP are known to behave at least
erratically. Some systems even appear to HANG for a while when
they receive T/TCP SYN+Push. Most systems will just send back
SYN+ACK, and wait for the third ACK to establish the connection.

/Matti Aarnio <matti.aarnio@tele.fi>

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu