Slow ubuntu ssh/telnet login prompt

in this discussion:

http://ubuntuforums.org/showthread.php?t=1842371

vi /etc/nsswitch.conf
find line “hosts: files mdns4_minimal [NOTFOUND=return] dns mdns 4 mdns”
change to
"hosts: files dns"

the login prompt will show up instantly

also, you can  move /etc/motd  away to disable the welcome message of telent

Windows XP windows size default is too small

The default vaule is 64K, it will impact the throughput test.

You need to modify the value if you want to get good throughput test result.

pptpd debug

start pptpd in debug mode:
pptpd -d

read the debug log in syslog:
cat /var/log/syslog

[problem]
connection failed, and debug message show "mppe required but peer refused" :
you need to force the client to use mppe encryption or close the mppe encryption option on server.

pptp client can't get dns server ip:
set the ms-dns option on the server side, let the client can get ip.

Packet out of order problem

The IP header is 32 bytes in normal situation.
If it is not, the packet ID's address we read may be wrong, we will got wrong ID and cause out of order.

This will cause serious speed impact because the client will ask host to transfer the right packet again.

It can be solved by enable the IP header realigned to 4 byte features on you wireless driver. (It should be enable by default)