Sudden onset ftp problem - can't ftp through vpn

[Rick Stevens]

On 07/02/2014 06:49 AM, Bill Oliver issued this missive:
>
> Another update.  It only happens when trying to send to my virtual
> machine -- I can ftp to at least two other places just fine using vpn.

I hit a similar thing on my F19 machine. The fix I had was (as root):

	echo "0" >/proc/sys/net/ipv4/tcp_sack

(I did this on the advice of our in-house network guru) I then added
these to the end of my /etc/sysctl.conf file so it gets set on the next
boot as well:

	# Speed up FTP uploads...
	net.ipv4.tcp_sack = 0

Seems to have solved the problem. It appears that there are some routers
or firewalls or VPNs that screw up the SACK on some transactions. Try
the first thing (the echo command) and see if it helps. If so, then do
the sysctl.conf stuff.
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- Rick Stevens, Systems Engineer, AllDigital    ricks at alldigital.com -
- AIM/Skype: therps2        ICQ: 22643734            Yahoo: origrps2 -
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-              Where there's a will, I want to be in it.             -
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