[gentoo-user] How do I change MSS separately from MTU?

[Walter Dnes]

Seeing discussions about best MTU/MSS for MLPPP on my ISP's forum, I
asked about the optimal settings for a standard DSL connection.
Because of the way ATM cells line up, the optimal MSS is 1408.  This
would normally imply MTU 1448, because MTU is normally MSS + 40.  The
optimal setting is apparently MTU 1492 and MSS 1408.  I tried forcing
MSS to 1408 in my routing config (/etc/conf.d/net), but that also
forces the MTU to 1448.  Is there a way to do them separately?

  The only suggestion I've found via Google is iptables "mangle".  Does
it manage to change MSS without changing MTU?  If so, what is the
invocation in the "mangle" table?

-- 
Walter Dnes <waltdnes@××××××××.org>