server-11.0.alpha20240611-x86-64 обновленный до Sisyphus

# rpm -qa | grep netpolice
netpolice-filter-1.01-alt5.1.x86_64
netpolice-main-1.02-alt3.2.x86_64

Настроил c-icap, указав ему использовать библиотеку srv_url_filter.so из пакета netpolice-filter: Service url_filter srv_url_filter.so. 
Настроил squid, конфиг из пакета squid-conf-host2cat.
Настроить host2cat. 

Сервис стартует успешно, однако:
# c-icap-client -s url_filter -i localhost -p 1344
ICAP server:localhost, ip:127.0.0.1, port:1344

OPTIONS:
	Allow 204: No
	Allow 206: No
	Preview: -1
	Keep alive: No

ICAP HEADERS:
	ICAP/1.0 500 Server error
	Server: C-ICAP/0.5.10
	Connection: close
	ISTag: "CI0001-XXXXXXXXX"

В логах /var/log/c-icap/access.log:
127.0.0.1 127.0.0.1 OPTIONS url_filter 500

При этом, если вместо url_filter c-icap настроить, например с Service echo srv_echo.so, то:
ICAP server:localhost, ip:127.0.0.1, port:1344
OPTIONS:
	Allow 204: Yes
	Allow 206: No
	Preview: 1024
	Keep alive: Yes

ICAP HEADERS:
	ICAP/1.0 200 OK
	Methods: RESPMOD, REQMOD
	Service: C-ICAP/0.5.10 server - Echo demo service
	ISTag: "CI0001-XXXXXXXXX"
	Transfer-Preview: *
	Options-TTL: 3600
	Date: Sat, 09 Nov 2024 06:13:49 GMT
	Preview: 1024
	Allow: 204
	X-Include: X-Authenticated-User, X-Authenticated-Groups
	Encapsulated: null-body=0