Re: [uml-user] Something about IP's of tap-devices on the host

[Jan H. <bu...@uc...>]

On Mon, Nov 25, 2002 at 05:29:11PM +0000, Matthew Bloch wrote:
> On Monday 25 November 2002 17:03, James Neal wrote:
> > On Mon, 2002-11-25 at 11:17, James Neal wrote:
> > > You could always treat those TUN interfaces as Point-to-point interfaces
> > > by giving them 32 bit netmasks and appropriate routing-table entries.
> >
> > Oh, it should be noted that although this 32bit netmask thing works, a
> > more popular-- and much easier-- way to do it is to bind all the
> > interfaces together into a bridge using the kernel Ethernet Bridging
> > module and bridge-utils. (http://bridge.sourceforge.net/)
> 
> ...providing you don't have any concerns about one UML being able to sniff 
> others' traffic on the same bridge.

Note 1: All interfaces on one host, tap or real, can share the same IP
address! The routing table includes interface name, so it does not use
the local IP and remote hosts always see only one interface, so no
problem there either. Been there, done that.

Note 2: Bridge is quite a cpu hog. i486/66 we used as router had hard
times bridging four 10Mbit interfaces. I did not try that with with
taps, but I would expect that to eat some CPU too. So for many umls it's
really better to set each connection as peer-to-peer (IIRC the uml_net
does that automatiaclly anyway (for host, you must do it right inside
uml).

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						 Jan 'Bulb' Hudec <bu...@uc...>