Re: [Story] When IPv6 Fixes IPv4 Peering Issues

[Jon Lewis <jlewis () lewis org>]

On Mon, 13 Jun 2022, Brie wrote:

> Who knows...  Hard to know if I'm taking a different network path or just 
> going through the same routers but bypassing whatever is blocking the 
> packets.

You might be able to infer that from the hops that show up in traceroutes.

> I went so far as to even randomize source/dest ports on each end in case it 
> was some sort of misguided filtering (ie:  port 12345 -> 54321 instead of 
> 12345 -> 12345).

That really makes it odd.  If you tried changing the src/dst ports with 
v4, and your VPN traffic still would not pass, but iperf would, what kind 
of filtering/breakage could CL or Comcast have that would just stop your 
VPN traffic regardless of ports?

I wonder if this is a misguided/misbhaving filter rule, or something 
actually broken eating your packets.  Having dealt with something far 
stranger many years ago, I totally get the aspects of "big telco can't 
help / won't let you even talk to someone who can understand your 
explanation of the issue" and "I don't care how I solve this, as long as I 
can make the issue go away."


----------------------------------------------------------------------
 Jon Lewis, MCP :)           |  I route
 StackPath, Sr. Neteng       |  therefore you are
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