Outbound TCP transfers very slow in NAT mode

[Peter Rindfuß]

I have vbox 2.1.5r43070, host win xp pro sp3, guest opensuse 11.0, all x86, in a fast ethernet lan environment (100 Mbit/s both ways). I noticed that in NAT mode, downloads from a network server to the vm run at the expected speed of up to 10 Mbytes/s (depending on the protocol used), whereas uploads are about 30 times slower (~330 kbytes/s). In host interface mode, both directions work at full speed. This was tested with ftp, smb and scp. Peter

[vasily Levchenko]

Does anything change with 2.2.2?

[Peter Rindfuß]

Not really. My last test with 2.2.2 and ftp: download ~ 11 MB/s upload ~ 600 kB/s Should be 11 MB both ways (as is in bridged mode). Peter

[vasily Levchenko]

Replying to rindfuss:

Not really. My last test with 2.2.2 and ftp: download ~ 11 MB/s upload ~ 600 kB/s Should be 11 MB both ways (as is in bridged mode). Peter

Hello Peter, Does it depend on chosen protocol? can you check e.g. if the scp upload/download has other ratio?

[Peter Rindfuß]

Replying to Hachiman:

Replying to rindfuss:

Not really. My last test with 2.2.2 and ftp: download ~ 11 MB/s upload ~ 600 kB/s Should be 11 MB both ways (as is in bridged mode). Peter

Hello Peter, Does it depend on chosen protocol? can you check e.g. if the scp upload/download has other ratio?

Just tested: scp shows the very same problem in NAT mode. Bridged mode is fine, again.

[ronon]

Replying to rindfuss:

Not really. My last test with 2.2.2 and ftp: download ~ 11 MB/s upload ~ 600 kB/s Should be 11 MB both ways (as is in bridged mode). Peter

I have similar problem on WinXP Pro SP3 Guest running on WinXP Pro SP3 Host.

[Frank Mehnert]

The NAT send performance should have notably increased with VirtualBox 3.0.2, can you confirm that?

[vladie]

Replying to Hachiman:

Does it change for you with ​3.0.6_B1?

Just tested, bug IS NOT fixed :( Downloads ~30mb/s, uploads ~1.3mb/s

[Frank Mehnert]

vladie, please attach a VBox.log file of such a 3.0.6 Beta 1 VM session to this defect.

[vladie]

vbox defect demonstration log

[vladie]

i've added log. i've started VM, tried to upload file throught NAT, then shutdowned VM.

[vladie]

just tested in 3.0.6 release, bug still exists and very annoying :(

[Frank Mehnert]

Any difference when using the E1000 device emulation? There are E1000 drivers even for WinXP available on the internet ...

[vladie]

just tried with e1000 desktop, problem persists:(

[Peter Rindfuß]

In 3.0.10, the problem is still there in the standard configuration. But if I increase buffer sizes according to 9.12.3 "Tuning TCP/IP buffers for NAT" in the docs, I get an almost optimal result: Outbound transfers are now only 10% below the maximum speed. I have set all 4 buffers to the max value of 1024 kBytes.

[vasily Levchenko]

Does it change in 3.1?

[Ben Nemec]

No, I was having the same problem with a Win XP guest on Kubuntu 9.10 in 3.1.0. Fortunately, the TCP/IP buffer tuning seems to have largely fixed the problem for me too. Also, for reference the relevant section of the manual is now 9.14.3.

[vasily Levchenko]

Replying to nemebean:

No, I was having the same problem with a Win XP guest on Kubuntu 9.10 in 3.1.0. Fortunately, the TCP/IP buffer tuning seems to have largely fixed the problem for me too. Also, for reference the relevant section of the manual is now 9.14.3.

Thanks for feedback. Probably your experience could be added on ​HOWTO page.