[HLUG] when ever sending large emails drops my net connectiion- why

[Andrew Hodgson]

Hi Julian,

I have no idea how to do this in IpCop, it will need to be done in the startup script that starts the modem up, possibly /etc/rc.d/rc.local, but I could be completely off the mark.  Of course the obvious way would be through the web GUI, but as you asked this question here, I take it there is no option to change the MTU in there?

I tend to use routers as I can pick cheap ones up for £20 on Ebuyer, they take less electricity to run and if you don't have an old machine, then they are the best option.

Andrew.

-----Original Message-----
From: herefordshire-bounces at mailman.lug.org.uk [mailto:herefordshire-bounces at mailman.lug.org.uk] On Behalf Of Julian Robbins
Sent: 21 May 2006 13:46
To: Herefordshire Linux Users Group.
Subject: Re: [HLUG] when ever sending large emails drops my net connectiion- why

Andrew Hodgson wrote:
> Hi,
>
> MTU is the probable issue here.  The main MRU/MTU setting to use on BT
> exchanges is 1500, with the MSS set to 1460.  Lowering the MTU is needed
> on some ISPS, for example I had a friend on virgin.net who had exactly
> the same problem, and I put the MTU to 1430 and it worked better.
>   
Hi Andrew

How and where do I do that?

Julian
> Andrew.
>
> -----Original Message-----
> From: herefordshire-bounces at mailman.lug.org.uk
> [mailto:herefordshire-bounces at mailman.lug.org.uk] On Behalf Of Julian
> Robbins
> Sent: 21 May 2006 12:27
> To: Herefordshire Linux Users Group.
> Subject: [HLUG] when ever sending large emails drops my net connectiion
> - why
>
> Hi
>
> Hope the mtg went ok, list seems quiet these days !!
>
> I've had a ongoing problem , i want to fix - any suggestions, fixes 
> gratefully recd!
>
> If I sent an email over roughly, 500k, my IPCop ADSL net connection
> drops.
>
> I've no reason to suspect IPCop as this has been going on for many 
> months, and i think it would have been fixed if it were a specific issue
>
> affecting IPCop.
>
> If i send the same mail via webmail its fine.
>
> I sent some tests via, my email smtp provider, fastmail.fm with and 
> without SSL. I also tried it with my ADSL provider Pro-net, same 
> problem, drops after getting only 21% through.
>
> I use IMAP with my email account, which is flawless apart from this.
>
> I'm using, FWIW Ubuntu Dapper, and Thunderbird 1.5.02, but I'm sure I 
> had same problems, running Breezy and older version of Thunderbird.
>
> IPCop has been there all the way along.
>
> My only other inkling is could it be a MTU issue? we suspect Pro-net (or
>
> their upstream provider) are doing strange things with MTU which might 
> cause issues, as we;ve had other strange ones occasionally.
>
> I haven't tried connecting with my windows laptop yet, thsi might at 
> least prove or disprove a couple of things.
>
> Any ideas ??
>
> Julian Robbins
>
>
>
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