How many protocols...

Stephen Sprunk wrote,

Thus spake "Magnus Boden" <>
> I wouldn't call it an isp if they only allowed tcp, udp and icmp.
> It should be all ip protocols.
> There can be a maximum of 256 of them. The isp shouldn't care what
> the ipheader->protocol field is set to.

There is at least one ISP here in the US that filters protocol 50 (IPsec ESP).
Does that mean they're really not an ISP?

If they are an ISP they are an aggressively clueless ISP. Why on Earth
would you block ESP? Some strange marketing ploy to charge more to
allow people to use VPNs? Ever heard of transport mode? Does it
actually cost them more to move ESP packets than TCP/UDP/ICMP packets?
Are they under some mistaken impression ESP would be a bandwidth hog?
Do they block GRE (protocol 47)? Do they block Checkpoint's FWZ
(protocol 94)? Or any of the other zillion VPN protocols (some which
ride over TCP and UDP too)?

Exactly which ISP does this? They deserve some public humiliation for
doing something that breathtakingly stupid to their customers.