impact of recent cisco vulnerability

[itojun@iijlab.net]

	because of recent cisco vulnerability, many ISPs installed filters
	that would drop mobile-ip4 (ip protocol type 55), both inbound and
	outbound at EBGP routers, as a countermeasure until they upgrade all
	of the cisco routers they have.  it would seriously impact the
	deployment/use of mobile-ip4.

	also swipe (53), sun ND (77), PIM (103) are getting filtered.  i don't
	think PIM operation will be affected by this as people wouldn't use
	PIM across AS borders.  not sure about swipe and sun ND.

itojun