If you have IMPBOX device you can mount handler via impbox without having
TCP/IP stack, use impbox_network directory :)
https://sordan.ie/search/?q=impbox - here you can get one

If you have TCP/IP stack for example ROADSHOW then you can mount it via 
bsdsocket.library, use then normal_network directory

Imp3 is here - https://aminet.net/package/mus/play/imp3

 PERMSSN    UID  GID    PACKED    SIZE  RATIO METHOD CRC     STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[Amiga]                    412     723  57.0% -lh5- c11e Mar 19 08:27 imp3handler.readme
[Amiga]                     79     100  79.0% -lh5- 49cb Mar 19 08:20 impbox_network/DEVS/DosDrivers/IB
[Amiga]                   1350    2335  57.8% -lh5- 2b5f Mar 19 08:20 impbox_network/DEVS/DosDrivers/IB.info
[Amiga]                     92     110  83.6% -lh5- 1c96 Mar 19 08:21 impbox_network/DEVS/MountList
[Amiga]                   5174   10464  49.4% -lh5- a250 Mar 19 08:20 impbox_network/L/imp3ib-handler
[Amiga]                     84     108  77.8% -lh5- fa34 Mar 19 08:20 normal_network/DEVS/DosDrivers/I
[Amiga]                   1346    2335  57.6% -lh5- 7aa6 Mar 19 08:20 normal_network/DEVS/DosDrivers/I.info
[Amiga]                     87     108  80.6% -lh5- 206a Mar 19 08:22 normal_network/DEVS/MountList
[Amiga]                   4554    9472  48.1% -lh5- 8a9a Mar 19 08:20 normal_network/L/imp3-handler
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total         9 files   13178   25755  51.2%            Mar 19 22:51