I have no idea what these config lines does in master.cf, can you explain?

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K F
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I have no idea what these config lines does in master.cf, can you explain?

K F
I've inherited a lot of postfix servers, and they contain some lines that I'm not really sure what does, maybe you can explain them to me?

an example from master.cf

yahoo     unix  -       -       n       -       3       smtp         -o syslog_name=postfix-yahoo

So this tells postfix something about the 'yahoo'?

In transport.regexp I see:

/yahoo(\.[a-z]{2,3}){1,2}$/  yahoo:
I guess that tells postfix about 'yahoo'.

As I can read the line, it tells it to have max 3 processes, and output hare to be sent to a specific syslog, right?

What happens if I just uncomment the "-o syslog_name=postfix-yahoo", will it then send the lines to the default maillog?

Furthermore I see a lot of lines in main.cf, that looks like this:

yahoo_initial_destination_concurrency = 1
yahoo_destination_concurrency_limit = 2
yahoo_destination_recipient_limit = 2
yahoo_destination_rate_delay = 1s

As I understand it, it limits the amount of mails sent per connection to the 'yahoo' defined servers?
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Re: I have no idea what these config lines does in master.cf, can you explain?

Noel Jones-2
On 1/8/2018 6:36 AM, K F wrote:

> I've inherited a lot of postfix servers, and they contain some lines
> that I'm not really sure what does, maybe you can explain them to me?
>
> an example from master.cf
>
> yahoo     unix  -       -       n       -       3       smtp        
> -o syslog_name=postfix-yahoo
>
> So this tells postfix something about the 'yahoo'?
>
> In transport.regexp I see:
>
> /yahoo(\.[a-z]{2,3}){1,2}$/  yahoo:
> I guess that tells postfix about 'yahoo'.
>
> As I can read the line, it tells it to have max 3 processes, and
> output hare to be sent to a specific syslog, right?
>
> What happens if I just uncomment the "-o syslog_name=postfix-yahoo",
> will it then send the lines to the default maillog?
>
> Furthermore I see a lot of lines in main.cf, that looks like this:
>
> yahoo_initial_destination_concurrency = 1
> yahoo_destination_concurrency_limit = 2
> yahoo_destination_recipient_limit = 2
> yahoo_destination_rate_delay = 1s
>
> As I understand it, it limits the amount of mails sent per
> connection to the 'yahoo' defined servers?


These lines limit mail to yahoo to a max of 1 mail per second
through 1 connection.  This is somewhat common for lower traffic
servers that might not have a lot of IP reputation for yahoo to
grade them on, to help prevent mail being seriously delayed or junked.

Logging is still to the default maillog but the lines will be
labeled eg. "postfix-yahoo/smtp" rather than "postfix/smtp"

The transport_maps entry matches recipients at various yahoo
domains, and directs them to the yahoo transport defined in master.cf.

The main.cf yahoo_destination_* entries define properties of the
yahoo transport (in master.cf).  Specifically, the
yahoo_destination_rate_delay limits the delivery to one mail per
second and automatically limits to one connection at a time.

Further documentation is found here:
http://www.postfix.org/documentation.html
http://www.postfix.org/postconf.5.html



  -- Noel Jones