What ICMP packets does state RELATED allow?

[Nathan Cassano]

Hi NetFilter Gurus,
        I have heard that ip_conntrack will allow ICMP packets pass that
are related to an existing connection. My question is what specific
related ICMP packets does conntrack allow for a given connection? Does
it allow Source Quench (--icmp-type 4) or Redirects (--icmp-type 5)?