netdb ?

Un grep rapide dans les sources suggère cette option sous cache_peer :

 no-netdb-exchange
 Disables requesting ICMP RTT database (NetDB).

inspiré par :

$ sed -n '/^NAME.*netdb/,/^$/p' src/cf.data.pre
NAME: netdb_filename
TYPE: string
DEFAULT: stdio:@DEFAULT_NETDB_FILE@
LOC: Config.netdbFilename
IFDEF: USE_ICMP
DOC_START
 Where Squid stores it's netdb journal.
 When enabled this journal preserves netdb state between restarts.
NAME: netdb_low
TYPE: int
DEFAULT: 900
LOC: Config.Netdb.low
DOC_START
 The low water mark for the ICMP measurement database.
NAME: netdb_high
TYPE: int
DEFAULT: 1000
LOC: Config.Netdb.high
DOC_START
 The high water mark for the ICMP measurement database.
NAME: netdb_ping_period
TYPE: time_t
LOC: Config.Netdb.period
DEFAULT: 5 minutes
DOC_START
 The minimum period for measuring a site. There will be at
 least this much delay between successive pings to the same
 network. The default is five minutes.
DOC_END

Debian Consultant @ DEBAMAX