postfix outgoing port ?

taiwf · 04-09-2006, 09:49 PM

HI,

I want to limit the bandwidth of outing email of my postfix mail server. I know the receiving port is
port25 but not sure what is the outgoing port. Does postfix use the same port to sending out the email?

I need to know the exact port number so to limit traffic base on port. By the way, i am also using amavis-new. Can anyone give me a hand ?

The shaper(cbq.init) config file i used is below:

DEVICE=eth0,100Mbit,10Mbit
RATE=500Kbit
WEIGHT=50Kbit
PRIO=5
RULE=,:25 [from anywhere going to port 25?]

d0odman · 04-09-2006, 10:11 PM

I believe mail goes out on 110. Try monitoring your ports as you send an email out from that server and see which one opens up.

taiwf · 04-09-2006, 11:13 PM

110 seems to be an pop3 local mail delivery, not the mail transport agent like postfix. If you open /etc/services , it mentions so....

I look up my mail.log , and i got sth like smtp[24xxx]. The port is different each time. I wonder if postfix use ramdon port to send out the email?

d0odman · 04-10-2006, 02:18 AM

Good call. It could very well be a random port for the email sending, which wouldn't be very good for your situation.

jed_reynolds · 07-06-2006, 10:59 AM

To see all my open connections, I often use
netstat -ntulp
This lists my open connections.

Most programs that use tcp connections initiate connections using ephemeral (random) high-numbered ports.

The rule you list below would be alright for connections to port 25,
but you might consider 465 as well, if you want to send to SSL enabled mail servers.