Hello Stefan, hello Patrick, I am not specifically involved in packaging sane but tried to reproduce your issue.
These were the steps I tested: - systemctl enable saned.socket - systemctl start saned.socket - activated the backend "test" in /etc/sane.d/dll.conf - added the "remote" server localhost to /etc/sane.d/net.conf - listed scanners with "scanimage -L" - made a test scan with "scanimage --device-name=net:localhost:test:0 > testscan" As far as I see this worked as exepected, so your issue might be related to the backend you are using. Unfortunately the information which backend you need is not included in your reports. Also you might make the output more verbose by - adding "SANE_DEBUG_DLL=255" to the Environment line in /lib/systemd/system/saned@.service - reload that change by "systemctl daemon-reload" - test again. Kind regards, Bernhard
# Buster/stable amd64 qemu VM 2020-08-18 apt update apt dist-upgrade apt install systemd-coredump net-tools mc sane-utils root@debian:~# systemctl status saned ● saned.service Loaded: masked (Reason: Unit saned.service is masked.) Active: inactive (dead) root@debian:~# systemctl start saned Failed to start saned.service: Unit saned.service is masked. root@debian:~# systemctl status saned.socket ● saned.socket - saned incoming socket Loaded: loaded (/lib/systemd/system/saned.socket; disabled; vendor preset: enabled) Active: inactive (dead) Listen: [::]:6566 (Stream) Accepted: 0; Connected: 0; root@debian:~# systemctl enable saned.socket Created symlink /etc/systemd/system/sockets.target.wants/saned.socket → /lib/systemd/system/saned.socket. root@debian:~# systemctl status saned.socket ● saned.socket - saned incoming socket Loaded: loaded (/lib/systemd/system/saned.socket; enabled; vendor preset: enabled) Active: inactive (dead) Listen: [::]:6566 (Stream) Accepted: 0; Connected: 0; root@debian:~# systemctl start saned.socket root@debian:~# netstat -anp | grep 6566 tcp6 0 0 :::6566 :::* LISTEN 1/init root@debian:~# systemctl status saned.socket ● saned.socket - saned incoming socket Loaded: loaded (/lib/systemd/system/saned.socket; enabled; vendor preset: enabled) Active: active (listening) since Tue 2020-08-18 10:54:43 CEST; 3min 38s ago Listen: [::]:6566 (Stream) Accepted: 0; Connected: 0; Tasks: 0 (limit: 3565) Memory: 52.0K CGroup: /system.slice/saned.socket Aug 18 10:54:43 debian systemd[1]: Listening on saned incoming socket. root@debian:~# systemctl status saned.service ● saned.service Loaded: masked (Reason: Unit saned.service is masked.) Active: inactive (dead) root@debian:~# echo localhost >> /etc/sane.d/net.conf benutzer@debian:~$ scanimage -L root@debian:~# journalctl -f Aug 18 10:59:49 debian systemd[1]: Created slice system-saned.slice. Aug 18 10:59:49 debian systemd[1]: Started Scanner Service ([::1]:49780). Aug 18 10:59:49 debian saned[2553]: saned (AF-indep+IPv6+systemd) from sane-backends 1.0.27 starting up Aug 18 10:59:49 debian saned[2553]: check_host: access by remote host: ::1 Aug 18 10:59:49 debian saned[2553]: init: access granted to benutzer@::1 Aug 18 10:59:53 debian saned[2553]: saned exiting Aug 18 10:59:53 debian systemd[1]: saned@0-::1:6566-::1:49780.service: Succeeded. root@debian:/etc/sane.d# sed -i 's/#test/test/g' /etc/sane.d/dll.conf benutzer@debian:~$ scanimage -L device `test:0' is a Noname frontend-tester virtual device device `test:1' is a Noname frontend-tester virtual device device `net:localhost:test:0' is a Noname frontend-tester virtual device device `net:localhost:test:1' is a Noname frontend-tester virtual device Aug 18 11:06:20 debian systemd[1]: Started Scanner Service ([::1]:49784). Aug 18 11:06:20 debian saned[2935]: saned (AF-indep+IPv6+systemd) from sane-backends 1.0.27 starting up Aug 18 11:06:20 debian saned[2935]: check_host: access by remote host: ::1 Aug 18 11:06:20 debian saned[2935]: init: access granted to benutzer@::1 Aug 18 11:06:25 debian saned[2935]: saned exiting Aug 18 11:06:25 debian systemd[1]: saned@1-::1:6566-::1:49784.service: Succeeded. root@debian:/etc/sane.d# mc -e /lib/systemd/system/saned@.service -Environment=SANE_CONFIG_DIR=/etc/sane.d -# Environment=SANE_CONFIG_DIR=/etc/sane.d SANE_DEBUG_DLL=255 +# Environment=SANE_CONFIG_DIR=/etc/sane.d +Environment=SANE_CONFIG_DIR=/etc/sane.d SANE_DEBUG_DLL=255 root@debian:/etc/sane.d# systemctl daemon-reload benutzer@debian:~$ scanimage --device-name=net:localhost:test:0 > testscan Aug 18 11:23:10 debian systemd[1]: Started Scanner Service ([::1]:49804). Aug 18 11:23:10 debian saned[3083]: saned (AF-indep+IPv6+systemd) from sane-backends 1.0.27 starting up Aug 18 11:23:10 debian saned[3083]: check_host: access by remote host: ::1 Aug 18 11:23:10 debian saned[3083]: init: access granted to benutzer@::1 Aug 18 11:23:10 debian saned[3083]: [sanei_debug] Setting debug level of dll to 255. Aug 18 11:23:10 debian saned[3083]: [dll] sane_init: SANE dll backend version 1.0.13 from sane-backends 1.0.27 Aug 18 11:23:10 debian saned[3083]: [dll] sane_init/read_dlld: attempting to open directory `/etc/sane.d/dll.d' Aug 18 11:23:10 debian saned[3083]: [dll] sane_init/read_dlld: using config directory `/etc/sane.d/dll.d' Aug 18 11:23:10 debian saned[3083]: [dll] sane_init/read_dlld: done. Aug 18 11:23:10 debian saned[3083]: [dll] sane_init/read_config: reading dll.conf Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `net' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `abaton' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `agfafocus' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `apple' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `avision' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `artec' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `artec_eplus48u' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `as6e' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `bh' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `canon' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `canon630u' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `canon_dr' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `cardscan' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `coolscan' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `coolscan3' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `dell1600n_net' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `dmc' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `epjitsu' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `epson2' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `epsonds' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `fujitsu' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `genesys' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `gt68xx' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `hp' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `hp3900' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `hpsj5s' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `hp3500' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `hp4200' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `hp5400' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `hp5590' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `hpljm1005' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `hs2p' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `ibm' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `kodak' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `kodakaio' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `kvs1025' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `kvs20xx' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `leo' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `lexmark' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `ma1509' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `magicolor' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `matsushita' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `microtek' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `microtek2' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `mustek' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `mustek_usb' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `mustek_usb2' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `nec' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `niash' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `pie' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `pint' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `pixma' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `plustek' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `qcam' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `ricoh' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `rts8891' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `s9036' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `sceptre' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `sharp' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `sm3600' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `sm3840' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `snapscan' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `sp15c' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `tamarack' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `teco1' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `teco2' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `teco3' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `test' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `u12' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `umax' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `umax1220u' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `v4l' Aug 18 11:23:10 debian saned[3083]: [dll] add_backend: adding backend `xerox_mfp' Aug 18 11:23:10 debian saned[3083]: [dll] sane_open: trying to open `test:0' Aug 18 11:23:10 debian saned[3083]: [dll] load: searching backend `test' in `/usr/lib/x86_64-linux-gnu/sane:/usr/lib/sane' Aug 18 11:23:10 debian saned[3083]: [dll] load: trying to load `/usr/lib/x86_64-linux-gnu/sane/libsane-test.so.1' Aug 18 11:23:10 debian saned[3083]: [dll] load: dlopen()ing `/usr/lib/x86_64-linux-gnu/sane/libsane-test.so.1' Aug 18 11:23:10 debian saned[3083]: [dll] init: initializing backend `test' Aug 18 11:23:10 debian saned[3083]: [dll] init: backend `test' is version 1.0.28 Aug 18 11:23:10 debian saned[3083]: [dll] sane_open: open successful Aug 18 11:23:10 debian saned[3083]: [dll] sane_control_option(handle=0x562a17e53820,option=0,action=0,value=0x7ffd939aea20,info=(nil)) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=0) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=1) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=2) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=3) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=4) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=5) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=6) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=7) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=8) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=9) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=10) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=11) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=12) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=13) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=14) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=15) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=16) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=17) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=18) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=19) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=20) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=21) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=22) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=23) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=24) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=25) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=26) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=27) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=28) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=29) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=30) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=31) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=32) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=33) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=34) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=35) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=36) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=37) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=38) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=39) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=40) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=41) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=42) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=43) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=44) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=45) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=46) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=47) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=48) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=49) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=50) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_option_descriptor(handle=0x562a17e53820,option=51) Aug 18 11:23:10 debian saned[3083]: [dll] sane_control_option(handle=0x562a17e53820,option=0,action=0,value=0x562a17e51810,info=0x7ffd939aea24) Aug 18 11:23:10 debian saned[3083]: [dll] sane_control_option(handle=0x562a17e53820,option=0,action=0,value=0x562a17e51810,info=0x7ffd939aea24) Aug 18 11:23:10 debian saned[3083]: [dll] sane_control_option(handle=0x562a17e53820,option=26,action=0,value=0x562a17e51810,info=0x7ffd939aea24) Aug 18 11:23:10 debian saned[3083]: [dll] sane_control_option(handle=0x562a17e53820,option=24,action=0,value=0x562a17e51810,info=0x7ffd939aea24) Aug 18 11:23:10 debian saned[3083]: [dll] sane_control_option(handle=0x562a17e53820,option=27,action=0,value=0x562a17e51810,info=0x7ffd939aea24) Aug 18 11:23:10 debian saned[3083]: [dll] sane_control_option(handle=0x562a17e53820,option=25,action=0,value=0x562a17e51810,info=0x7ffd939aea24) Aug 18 11:23:10 debian saned[3083]: [dll] sane_control_option(handle=0x562a17e53820,option=24,action=0,value=0x562a17e51810,info=0x7ffd939aea24) Aug 18 11:23:10 debian saned[3083]: [dll] sane_control_option(handle=0x562a17e53820,option=26,action=1,value=0x562a17e51810,info=0x7ffd939aea24) Aug 18 11:23:10 debian saned[3083]: [dll] sane_control_option(handle=0x562a17e53820,option=25,action=0,value=0x562a17e51810,info=0x7ffd939aea24) Aug 18 11:23:10 debian saned[3083]: [dll] sane_control_option(handle=0x562a17e53820,option=27,action=1,value=0x562a17e51810,info=0x7ffd939aea24) Aug 18 11:23:10 debian saned[3083]: [dll] sane_start(handle=0x562a17e53820) Aug 18 11:23:10 debian saned[3083]: [dll] sane_set_io_mode(handle=0x562a17e53820,nonblocking=1) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_select_fd(handle=0x562a17e53820,fdp=0x7ffd939ac778) Aug 18 11:23:10 debian saned[3083]: [dll] sane_read(handle=0x562a17e53820,data=0x7ffd939ac994,maxlen=8188,lenp=0x7ffd939ac77c) Aug 18 11:23:10 debian saned[3083]: [dll] sane_get_parameters(handle=0x562a17e53820,params=0x7ffd939ac5d4) Aug 18 11:23:10 debian saned[3083]: [dll] sane_read(handle=0x562a17e53820,data=0x7ffd939ac994,maxlen=8188,lenp=0x7ffd939ac77c) Aug 18 11:23:10 debian systemd[1]: saned@9-::1:6566-::1:49804.service: Succeeded. Aug 18 11:23:10 debian saned[3083]: [dll] sane_read(handle=0x562a17e53820,data=0x7ffd939ac994,maxlen=8188,lenp=0x7ffd939ac77c) Aug 18 11:23:10 debian saned[3083]: [dll] sane_read(handle=0x562a17e53820,data=0x7ffd939ac994,maxlen=8188,lenp=0x7ffd939ac77c) Aug 18 11:23:10 debian saned[3083]: [dll] sane_read(handle=0x562a17e53820,data=0x7ffd939ae1d8,maxlen=1976,lenp=0x7ffd939ac77c) Aug 18 11:23:10 debian saned[3083]: [dll] sane_cancel(handle=0x562a17e53820) Aug 18 11:23:10 debian saned[3083]: [dll] sane_close(handle=0x562a17e53820) Aug 18 11:23:10 debian saned[3083]: saned exiting