[ILUG] Bizarre networking problem

[Niall O Broin]

On 29 Feb 2008, at 15:22, paul at clubi.ie wrote:

> On Fri, 29 Feb 2008, Niall O Broin wrote:
>
>> s8A -> s8B        TCP D=22 S=32858 Syn Seq=3908249784 Len=0  
>> Win=24820 Options=<nop,nop,sackOK,mss 1460>
>
>> s8A -> s8B        TCP D=22 S=32858 Syn Seq=3908249784 Len=0  
>> Win=24820 Options=<mss 1460,sack 16843778-2895157918|>
>
> Wow, it's mangled the options.
>
> I'm guessing this router is also doing firewalling and/or NAT..

The router does NAT, though it is turned off for these connections.  
It also has firewall functionality, which is explained on page 248 of  
the manual, apparently - I can't tell, as the manual has < 150 pages.  
Spelunking around the nasty Windows configuration tool, I don't find  
it named as such - there is a packet filtering option, but there are  
none defined.

I'm 99.99% sure that this nasty nearly 10 year old ISDN router is the  
source of my woes. Why don't you replace it with a VPN, I hear you  
say? Bloody good question, I say, and I wish I knew the answer to it.


Niall