postfix mail queue - get bottleneck - Debian squeeze

Question

I have a problem with Postfix 2.7.1, Debian Squeeze:

• send and receive mail with no problem working locally,
• send e-mail outside work without a problem,
• the problem is when someone sends a large amount of mails e.g. 500-1000 and for example a lot of phrases such as "connection refused" or timeout or email falls into greylist, at that moment the queue on the server

mailq -

148425 Kbytes in 508 Requests.

qshape-p shows

T 5 10 20 40 80 160 320 640 1280 1280 +
TOTAL 571 9 9 26 95 153 278 1 0 0 0
domena.pl 369 6 7 17 60 107 172 0 0 0 0

domena.pl — is the domain of the server, the client sends them who make large mail amount (large as a large mail 500-1000).

And once someone sends to the server from outside the post office is the one This falls into the mail queue and waiting until the 508 is mails sent or returned to a user.

I do not know how to deal with this now, if someone had a similar problem? Let me know, I can give you more information if you need it.