CVE-2002-0515: Observable Discrepancy

IPFilter 3.4.25 and earlier sets a different TTL when a port is being filtered than when it is not being filtered, which allows remote attackers to identify filtered ports by comparing TTLs...

CVE-2002-0514: Observable Discrepancy

PF in OpenBSD 3.0 with the return-rst rule sets the TTL to 128 in the RST packet, which allows remote attackers to determine if a port is being filtered because the TTL is different than the default TTL...