I'm running KDE Platform Version 4.14.10, and all components (dolphin, konqueror, etc) cannot use SMB. Turning on the kdebug for kio_smb gives me the following when I type "smb://guest@192.168.6.20/core/" into any URL bar: kio_smb(21703) SMBSlave::auth_initialize_smbc: auth_initialize_smbc kio_smb(21703) SMBSlave::auth_initialize_smbc: smbc_init call kio_smb(21703) SMBSlave::stat: KUrl("smb://guest@192.168.6.20/core/") kio_smb(21703) SMBSlave::checkURL: checkURL KUrl("smb://guest@192.168.6.20/core/") kio_smb(21703) SMBSlave::checkURL: checkURL return3 KUrl("smb://guest@192.168.6.20/core/") kio_smb(21703) SMBUrl::updateCache: updateCache "/core/" kio_smb(21703) SMBSlave::auth_smbc_get_data: AAAAAAAAAAAAAA auth_smbc_get_dat: set user= guest , workgroup= WORKGROUP server= 192.168.6.20 , share= core kio_smb(21703) SMBSlave::auth_smbc_get_data: libsmb-auth-callback URL: KUrl("smb://192.168.6.20/core") and there it will hang. If I try again, it'll just replicate those lines. tcpdump shows nmb name queries for core, and then a TCP three-way handshake to the correct server, and then eventually a TCP teardown with FIN, etc. No data is exchanged on the connection. From the code, the next step is to check the password, but I can't figure out where it's hanging before that.
I should have mentioned that "mount_smbfs //core/core /mnt/core/" works just fine, and that using "core" in place of "192.168.6.20" results in the exact same behavior.
KDE 4 is pretty ancient stuff at this point in time. All the issues described here have been fixed in later versions. Everything works fine for me with KDE Frameworks 5.47.