PPTP extremly slow

RouterOS General
1

Hi all,

I have a following setup:

RB912 with 3G miniPCI card. PPP connection is configured as well as NAT. Everything works fine.

I’ve configured PPTP tunnel between PC (windows 8 ) and RB912 and that’s where the problem starts. PPTP tunnel connection is extremly slow. The speeds are 10% of the speed without tunnel. I am testing with TFTP client behind router (local network) to TFTP server on PC connected through PPTP .

PPTP server configuration is default (mschap1, mschap2, chaneg tcp-mss,…)

I’ve tried to experiment with MTU, MRU, MRRU. Tried to ping the router and figured out that the fragment starts above 1270 bytes. So I’ve changed MRRU to 1270 bytes as someone suggested windows 8 is using MRRU. Here is the configuration
interface pptp-server server print
enabled: yes
max-mtu: 1450
max-mru: 1450
mrru: 1270
authentication: mschap1,mschap2
keepalive-timeout: 30
default-profile: default-encryption

I’ve also experimented with changing mtu and mru but the behavior is the same. CPU load is 1-5% so that is not the problem.

What is the problem? Am I doing something wrong? I thought it would work out of the box with no problems.

2

I forgot to write that there are no firewall rules, just NAT and default mangle rules for change tcp mss.

I’ve tried it without NAT but the behavior is the same.

3

To answer to myself. It seems the problem is with TFTP. If I test it with FTP the speeds are OK.

I don’t know if I can change any settings to get TFTP to work any better because I’ll have a device in this case which uses only TFTP for software upgrade.