Usenet problem: single-packet articles??

Orange have just transferred me from dial-up (service closing down) to
broadband. (I have a 30-day period in which I can jump ship if I don't
like the service.) I've bought a secondhand Netgear DG834 ADSL modem /
Ethernet router (rather than using the USB modem supplied by Orange).

So far pretty much everything seems fine. (There was an outage of an
hour or last night. General problem, or my line still being fiddled
with?)

But I can only post Usenet articles of length not greater than the MTU
value of the router plus 238 bytes. (This is inferred from experimental
postings to a *.test group, using two different MTU values.) What is the
likely cause of this, and what can I do about it? E.g. is my router set
wrong; or are Orange somehow not handling NNTP correctly? (I can hardly
be the only one of their millions of customers still using Usenet - can
I?) :-)
--
Angus Rodgers
(twirlip@ eats spam; reply to angusrod@)
Contains mild peril

In message <(E-Mail Removed)>
at 20:46:40 on Thu, 13 Dec 2007, Angus Rodgers <(E-Mail Removed)>
wrote
>Orange have just transferred me from dial-up (service closing down) to
>broadband. (I have a 30-day period in which I can jump ship if I don't
>like the service.) I've bought a secondhand Netgear DG834 ADSL modem /
>Ethernet router (rather than using the USB modem supplied by Orange).
>
>So far pretty much everything seems fine. (There was an outage of an
>hour or last night. General problem, or my line still being fiddled
>with?)
>
>But I can only post Usenet articles of length not greater than the MTU
>value of the router plus 238 bytes. (This is inferred from experimental
>postings to a *.test group, using two different MTU values.) What is the
>likely cause of this, and what can I do about it? E.g. is my router set
>wrong; or are Orange somehow not handling NNTP correctly? (I can hardly
>be the only one of their millions of customers still using Usenet - can
>I?) :-)
>
For web browsing, I find the default 1492 on my Netgear does not work
for me. I go for 1440 on the router, but you also have to make sure
your PC MTU does not exceed the router MTU. You need something called
DrTCP for your PC. I guess similar would apply to NG also?

If you stay with Orange, do you have a minimum contract period? Have a
look at this web at the ratings
http://www.dslzoneuk.net/isp_ratings.php
Good luck if you do leave Orange and make sure they don't slam your line
--
Mike News

[I have to split even this brief reply in half! - Part 1.]

On Thu, 13 Dec 2007 21:05:25 +0000, Mike
<turnpike_user@turnpike_REMOVEuser.THIScomANDTHI S> wrote:

>For web browsing, I find the default 1492 on my Netgear does not work
>for me.

No problems yet except with Usenet.

>I go for 1440 on the router,

Both 1492 and 1458 (what it came with) seem to work.

>but you also have to make sure your PC MTU does not exceed the
>router MTU.

I didn't know my PC had one!

>You need something called DrTCP for your PC.

I'll Google for it.

>I guess similar would apply to NG also?

This problem is very specific to Usenet.
--
Angus Rodgers
(twirlip@ eats spam; reply to angusrod@)
Contains mild peril

[I have to split even this brief reply in half! - Part 2.]

On Thu, 13 Dec 2007 21:05:25 +0000, Mike
<turnpike_user@turnpike_REMOVEuser.THIScomANDTHI S> wrote:

>If you stay with Orange, do you have a minimum contract period?

18 months.

>Have a look at this web at the ratings
>http://www.dslzoneuk.net/isp_ratings.php

I did read some hair-raisingly bad reviews, which is why I went
for the £11.99/m. option with 30-day grace period, for existing
dial-up customers only.

>Good luck if you do leave Orange and make sure they don't slam your line

God, what's that?! And how do I prevent it? #-O
--
Angus Rodgers
(twirlip@ eats spam; reply to angusrod@)
Contains mild peril

In message <(E-Mail Removed)>
at 21:43:18 on Thu, 13 Dec 2007, Angus Rodgers <(E-Mail Removed)>
wrote
>>Good luck if you do leave Orange and make sure they don't slam your line
>
>God, what's that?! And how do I prevent it? #-O
>
It's where an ISP leaves a tag on your line (even though you don't have
a service with them) which means you can't move to another ISP.
Normally if you do have a service you'd get a MAC code so you can move
ISP's easily, but if you go at the end of a trial period, I don't know
how this would work with Orange

You can't prevent it, but you can complain to the ISPA if they do it
--
Mike News

Now can't post even tiny reply! Going berserk. 6th attempt!
--
Angus Rodgers
(twirlip@ eats spam; reply to angusrod@)
Contains mild peril

On Fri, 14 Dec 2007 22:39:14 +0000, I wrote:

>Now can't post even tiny reply! Going berserk. 6th attempt!

(Have e-mailed News.Individual.NET, hoping they can sort it out.
No suggestions in any of three NGs I have asked. When I get PC
problems at all, they always seem to be especially weird ones!)
--
Angus Rodgers
(twirlip@ eats spam; reply to angusrod@)
Contains mild peril

Angus Rodgers <(E-Mail Removed)> wrote:

>On Fri, 14 Dec 2007 22:39:14 +0000, I wrote:
>
>>Now can't post even tiny reply! Going berserk. 6th attempt!
>
>(Have e-mailed News.Individual.NET, hoping they can sort it out.
>No suggestions in any of three NGs I have asked. When I get PC
>problems at all, they always seem to be especially weird ones!)

I don't actually know much about this but MTU related problems to specific
destination are often caused by MTU path discovery not working because
something (often the user's firewall) is blocking the ICMP packets that
make it work.


Your computer sends packet with a do not fragment flag set and anything on
the path which can't pass it without fragmentation sends back an ICMP which
cause your computer to send smaller packets. If it doesn't get the ICMPs
back you will not be able to send a packet bigger than whatever that path
can pass.

--

nospam wrote:
> Angus Rodgers <(E-Mail Removed)> wrote:
>
>> On Fri, 14 Dec 2007 22:39:14 +0000, I wrote:
>>
>>> Now can't post even tiny reply! Going berserk. 6th attempt!
>> (Have e-mailed News.Individual.NET, hoping they can sort it out.
>> No suggestions in any of three NGs I have asked. When I get PC
>> problems at all, they always seem to be especially weird ones!)
>
> I don't actually know much about this but MTU related problems to specific
> destination are often caused by MTU path discovery not working because
> something (often the user's firewall) is blocking the ICMP packets that
> make it work.
>
>
> Your computer sends packet with a do not fragment flag set and anything on
> the path which can't pass it without fragmentation sends back an ICMP which
> cause your computer to send smaller packets. If it doesn't get the ICMPs
> back you will not be able to send a packet bigger than whatever that path
> can pass.
>
Google TCP window size: you may find teh problem is lurking there.

With supert high speed networking coming out, enormous window sizes have
been added to many OS kernels and these 'break' older equipment.

The trick is to turn them off and see if things improve.