[AusNOG] Telstra Business - known issues??

[Ross Wheeler]

On Sat, 27 Apr 2019, Jacob Taylor wrote:

> It's a pretty common thing these days to see ISPs blocking TCP 25 
> inbound, even on connections that purport to be 'business' grade. I 
> assume this is because every man and his dog uses GSuite or O365 today.

Yes, but I'd have thought (perhaps foolishly) there would be notice before 
they did that.


> How did you verify no SYNs hitting the server? tcpdump?

Yes, managed to gain internal access to their network today through a 
raspberry pi that created a reverse tunnel back out to one of my boxes.
>From there I could access the router and redirected the port 25 port 
forward to the pi and used tcpdump.

Hoping it was just port 25 blocked, I tried various other ports, both well 
known and "random" services both priviliged and non-priv ports (ie, below 
1024 and above), and confirmed that none of them were being received.

Yes, it's entirely possible it's the (telstra supplied) router.
But it's equally possible it's within telstras network.

Whatever is its, it's causing significant operational problems for the 
client. Mail is only the tip of the iceberg, various other services 
(including VPN) also stopped working at the same time.

R.