Coda File System

Re: CODA clients implement incoming TCP connections from CODA server??

From: Greg Troxel <>
Date: 26 Jan 1999 14:15:57 -0500
  handling multi-homed addresses can cause some problems however.

I've noticed this - my workstation has two Ethernets, a wavelan and a
ppp link, and my coda server has two Ethernets.  If I try to push coda
packets over the 100 Mb/s link I end up losing (kernel crashes on the
client) (since that isn't the 'primary' address), but I have been
waiting to upgrade to 5.0.0 and debug this better before submitting a

  It also restricts you to one client behind the firewall, as
  multiple-clients ends up having the side-effect packets go to the wrong
  client the second time :(.  A firewall proxy that understands quite a bit

I meant just plain filtering router, not nat-proxy-firewall; I don't
think the problem you describe (with NAT) will be present - the inside
machines have real addresses that are per-machine unique, just like
normal.  (I realize that some people suffer from NAT and not just

The TCP SFTP sounds very cool, and would make the IAB types happy too,
since it would then be clear that large Coda transfers compete fairly
with TCP as far as congestion control goes.  Right now this may or may
not be true, but it certainly isn't obvious.

I have two scenarios for MTU problems:

 576 byte MTU on a PPP line, and a remote ethernet
  [happened to me, and was so bad that I upped the MTU]

 mobile ip/ipsec, where the mtu gets dropped 20 or more bytes for the
 extra headers 

I think TCP SFTP would effectively fix both of these problems - it's
mostly the file fetches that cause me trouble.

        Greg Troxel <>
Received on 1999-01-26 14:19:51