Slow speed behind pfsense

stephon

Hello all

I have a pfsense 1.2.3 installed on a server with 2 broadcom NICs.
The configuration as below:

public IP <–-> pfSense <---> private IP

In the private side, a machine named A wants to connect a SMTP server outside the pfSense and send a mail with 300k attachment, but spends about 2 minutes to send. (1kB/s average)

Another machine named B has public IP, doing the same thing as A, only spends 1 seconds to send.

top -SH & netstat -ni don't see anything irregular.

What the situation would it be? and how to solve it?

(Note: my pfSense has run squid, but the loading is very low)

Thanks a lot

stephon

Hello
Does anyone know about it?

Thanks a lot

GruensFroeschli

So are you currently running squid?
If yes: search the forum for "slow internet with squid". There are dozens of threads about this.

stephon

Hello

Yes, I've running squid on it,
but it seems fine to download a file behind pfSense, it usually runs at 3~4MB/s
but while send a mail with 300k attachment to the smtp server outside pfSense,
it runs about 5~7sec to finish a mail

this thing confuses me a while ???

Cry Havok

Can you see the dialog or log messages between your SMTP device and the remote server? The problem may be with one of those, not pfSense.

stephon

Hello Cry

Seems not the problem of SMTP server
while I disable firewall and use public IP to send mail
it only spends < 1s to finish

there is nothing wrong about nat settings…

and I've checked if this would be a MTU mismatch problem, but seems not
all pfsense, machines inside pfsense, and SMTP server were the same MTU as 1500

danswartz

Without seeing a packet capture during a slow SMTP send, it's hard to comment.

leoalfa09

Try using your pfsense box without other services like squid, disable all and try???

cmb

@danswartz:

Without seeing a packet capture during a slow SMTP send, it's hard to comment.

^ this. If you can attach a pcap of only that SMTP traffic we can probably tell you why. My first guess is you have a PMTUD problem of some sort. Dropping the MTU on your mail server to 1400 is one way to test that.

stephon

Thanks all,
I found it might be a MTU problem while I tuning the MTU down on mail server….