Re: Change MTU size on a Vax 6000 using Multinet 3.2 Rev B?

From: The CO (the_xo_at_yahoo.com.au)
Date: 07/04/05 

Date: Mon, 04 Jul 2005 22:02:08 +0930

huw.davies@kerberos.davies.net.au wrote:
> Stefaan A Eeckels <tengo@deletemeecc.lu> wrote:
>
>>On Sun, 03 Jul 2005 14:32:41 -0000
>>huw.davies@kerberos.davies.net.au wrote:
>
>
>>>Even cheaper, get a Linksys WRT54G (around $99) and get a free wireless
>>>network as well. With the stanard Linksys software you can set the MTU
>>>on the outgoing ("Internet") port to practically anything.
>
>
>>Will it work in bridging mode? Last time I looked, it insisted
>>on NATing everything.
>
>
> I suspect with the standard Linksys firmware you may well be right and
> I can't check this as I run a non-standard configuration.

Gentlemen, thanks for all your help.

Huw, thanks for forwarding this to JB, he was able to provide some
guidance on how multinet sets parameters. For the record, it requires
creating an se0_configure.com file with the appropriate interface
commands in the multinet_root directory so that they are enacted by
start_multinet.com as the system loads. They cannot be changed
dynamically, only at startup it seems. Thinking about it, that makes
complete sense and I'm obviously clueless for not realising that.
Anyway, it seems to work, only snag is it requires a complete reboot.
I have set the mtu to 1468 bytes and it accepted that fine, however the
original problem is still present. I will try tweaking the size
downwards and see if there is a reasonable size at which it works,
otherwise it seems we have not found the root of the problem.
I've decided that I am not going to drop the packet size down by more
than 100 bytes or so, after that the performance hit will likely start
to bite a bit more than I like.

If it doesn't spring to life, I'm going to hang a pc with Ethereal
across the Vax network connection and see what the hell is going on
here. I'm informed that the packet size negotiation wasn't implemented
until Ver 3.3, so theoretically it shouldn't be using ICMP to negotiate,
which is a bit odd seeing as how turning off ICMP seems to have created
the problem. One way or the other I'm going to get to the bottom of
this..... 

-- 
Geoff Roberts
IT Support
Saint Mark's College
Port Pirie, South Australia
geoffrobx@stmarksx.ppx.catholicx.edux.aux
Remove all x's from email address....

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