tOMPSON’s blog

As I wrote in my post about my mail server configuration I am using postfix as MTA for my emails. This week a friend had problems to send me an email containing some attachments. He got the following error message from my server:

SMTP error from remote mail server after MAIL FROM:<anyone@anywhere.com>
SIZE=16282613:
host example.net [87.230.24.156]: 552 5.3.4 Message size exceeds fixed limit

I was a bit confused because I did not set any limit. After checking the postfix manual and running the following commands

postconf -d (showing the default settings)
postconf -n (showing explicitly configured settings)

I found out that the default maximum message size is configured like

message_size_limit = 10240000

which means about 10MB. I ran the following commands to adjust the limit:

postconf -e "message_size_limit = 102400000"

Now I am able to receive mails with a maximum size of about 100 megs. Additionally I change the maximum mailbox size with the following command:

postconf -e "mailbox_size_limit = 512000000"
postconf -e "virtual_mailbox_limit = 512000000"

Linux, Security