Random Information ...others might find it interesting too.

Remote serial port connection on FreeBSD

For debugging purposes I needed to provide serial access to a device attached to a remote machine without giving any other type of remote access. This doesn't sound too hard but surprisingly it's quite confusing and information is sparse. Making Google do it's magic I ended up with these three options:

  • ser2net
  • socat
  • remserial

ser2net: Follows the RFC 2217 standard which is good, unfortunately there doesn't seem to be many clients around. The only ones I could find that were free was Kermit (Open Source) and HW VSP by the HW-Group (Freeware).

socat: Seems to be awesome and very versatile if you know what you're doing, honestly the documentation put me off...

remserial: Emulates a serial port remotely, proprietary, very minimalistic (doesn't really output any errors) and doesn't run on Windows unfortunately.

As Windows wasn't a requirement in this case I ended up running remserial as it just worked and did what it was supposed to do without any additional applications.

On the server (-p port (TCP), -s speed raw, /dev/cuau0 being the serial device in my case):
remserial -d -p 32323 -s "115200 raw" /dev/cuau0 &

On the client (-r remoteipadress, -p port (TCP), -l redirected-serial-port):

kldload ptmx
remserial -d -r <ipaddress> -p 32323 -l /dev/remser1 /dev/ptmx &

All set, now you just need to connect as you usually do but using /dev/remser1 as the serial port instead.

Tested on FreeBSD 10.1

Anonymous NFSv4 shares on FreeBSD

Tested on FreeBSD 10 and above:

  • /etc/sysctl.conf
    vfs.nfsd.server_min_nfsvers=4
  • /etc/exports
    /path/to/somewhere -ro -mapall=nobody -alldirs -network 192.168.1.0/24
  • /etc/rc.conf
nfs_server_enable="YES"
nfsv4_server_enable="YES"
nfsuserd_enable="YES"

This will share your directory to all clients on that have 192.168.1.X as IP address with read only permissions on your network. Have in mind that all clients don't support v4, OpenELEC for instance only supports up to v3 which you'll need to adjust in your sysctl accordingly.

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