Cannot copy file_name: The path is too deep

Ever get this error “Cannot copy file_name: The path is too deep” when trying to drag-and-drop a file?  Were you going through a firewall?

I recently came across this error and it had us stumped for quite a while.  I found several articles online that didn’t quite identify it correctly or didn’t apply to my situation.  After digging around on the knowledge base of the firewall manufacture, Check Point in this case, I came across a real solution that worked.  It wasn’t easy to find, even on their site because the situation wasn’t the same, but I figured “what the heck, I’ll try it”, and it worked. 

The problem had to do with the default windowing size allowed through the firewall.  If you aren’t familiar, “windowing” is how TCP negotiates the transfer of data.  It is variable and starts out slow until it can negotiate an acceptable packet-to-acknowledgement rate for both parties.  For example, first we exchange packets by me giving  you one packet and you responding (acknowledging) that you received it.  Then we try say 10 packets to one, if that worked without corruption, we increase it.  So on and so forth until we get to a maximum agreeable rate that both of us are comfortable with and we get data transfered at a much higher speed.  All that to say this…

Check Point firewalls have a max windowing size of 10K by default.  This sometimes gives you the “Path is too deep” error, espescially when on a LAN going to a DMZ or some other interface on the firewall.  To fix it you will want to do the following:

To increase the window size, run the fw ctl set int fwtcpstr_max_window 65536 command.

Note: This command does not survive a reboot.

To make the command survive a reboot:

1. On Linux or SecurePlatform, edit the $FWDIR/boot/modules/fwkern.conf file using vi.
2. Set a parameter name to a value, e.g.,
   fwtcpstr_max_window=65536
3. Run the fw ctl get int fwtcpstr_max_window command to verify whether the new value is applied on the OS properly.

After the procedure completes, users should be able to successfully copy the files.