I'm running 3.0_STABLE on i386, and I've mounted a samba filesystem
across the network using mount_smbfs.  This command works pretty well:

  find /mnt/backup -name '*' -print

So I can tell that the mount point is working etc.

But when I try to copy a bunch of files over to this partition using tar or cpio, I get 

  tar: Failed write to file albums/drainage-problem/img_1104.jpg (Connection timed out)

or

  cpio: Cannot create /mnt/backup/home/www/gallery/albums/drainage-problem (Connection timed out)

Ping times to the samba server are consistent and quick:

  /sbin/ping -i 1 backup
  PING backup (192.168.1.6): 56 data bytes
  64 bytes from 192.168.1.6: icmp_seq=0 ttl=64 time=0.609 ms
  64 bytes from 192.168.1.6: icmp_seq=1 ttl=64 time=0.618 ms
  64 bytes from 192.168.1.6: icmp_seq=2 ttl=64 time=0.611 ms
  64 bytes from 192.168.1.6: icmp_seq=3 ttl=64 time=0.405 ms
  64 bytes from 192.168.1.6: icmp_seq=4 ttl=64 time=0.627 ms
  64 bytes from 192.168.1.6: icmp_seq=5 ttl=64 time=0.507 ms

I don't know whether this is a samba problem, a netbsd problem, a
networking problem, or what.  Any ideas on what to look into next?