Choppa wrote:
> Hi,
>
> I'm using a Cisco 877 router. I've got it generally working with both
> IPv4 and IPv6 but am having trouble accessing some sites like
> microsoft.com.
>
> Could someone take a look at my config to see what could be causing
> these problems?

On 21CN? MTU issue?

Try -

interface Dialer1
  ip tcp adjust-mss 1452

-- 
Matt Balyuzi

On Nov 1, 9:22 pm, Matt Balyuzi  wrote:
> Choppa wrote:
> > Hi,
>
> > I'm using a Cisco 877 router. I've got it generally working with both
> > IPv4 and IPv6 but am having trouble accessing some sites like
> > microsoft.com.
>
> > Could someone take a look at my config to see what could be causing
> > these problems?
>
> On 21CN? MTU issue?
>
> Try -
>
> interface Dialer1
>   ip tcp adjust-mss 1452
>
> --
> Matt Balyuzi

Yes on 21CN.

That fixed it. Should I set the MTU on any devices on the LAN? is
there a way to do this automatically?

Choppa wrote:
<snip>
> 
> Yes on 21CN.
> 
> That fixed it. Should I set the MTU on any devices on the LAN? is
> there a way to do this automatically?

I was under the impression that only  be  lines needed a smaller MTU and
BT used 1500.

Eddie Pounce wrote:
> Choppa wrote:
> <snip>
>> Yes on 21CN.
>>
>> That fixed it. Should I set the MTU on any devices on the LAN? is
>> there a way to do this automatically?

No need to set anything on the machines on the LAN, this will clamp the 
MTU for traffic traversing the adsl line only, which is what you want.

> I was under the impression that only  be  lines needed a smaller MTU and
> BT used 1500.

There seems to be an issue on 21CN with the router happily negotiating a 
1500 byte MTU, but the BT kit ignoring this.... I've certainly seen that 
on my line, hence the need to insert the MSS clamp.

I think there's also an option on the control pages to apply the mss 
clamp on the aaisp router if need be.

I imagine aaisp should be able to advise further if reported this to them.

-- 
Matt Balyuzi