Topic: ssmtpd - per host concurrency limit reached

[thomas_chan]

Anyone can assist to configure the concurrency limit for ssmtpd service. I have been done the followings but it still doesn't work :-

- login as root
- type :
config setprop ssmtpd ConcurrencyLimit 200
config setprop ssmtpd ConcurrencyLimitPerIP 20
signal-event email-update

I used telnet to test port 465 for ssmtpd service and find out the maximum concurrent connection is only allow 5 !!

[mdo]

Although it is called 'concurrency' in the logfile ("tcpsvd: info: concurrency 27722 192.168.10.2 1/5"), "ConcurrencyLimit" seems NOT to be the parameter name for the smtp services.

Judging from the smtp service settings:

config show smtpd
smtpd=service
    Authentication=disabled
    Instances=60
    InstancesPerIP=5
... cut ...

I would try as follows:
config setprop ssmtpd InstancesPerIP xx
config setprop ssmtpd Instances xx (if to change that at all)

Michael

[thomas_chan]

Michael,hy

Thanks !! Just test OK after followed your changes.

[robwellesley]

I would try as follows:
config setprop ssmtpd InstancesPerIP xx
config setprop ssmtpd Instances xx (if to change that at all)

Michael

Hi Michael

Due to xtras roll out of theor port 25 policy http://www.xtra.co.nz/port25 we are setting up customers Laptop users to auth on 465 and seeing this 'error' occasionally.  Any advice on useful settings?

Rob Wellesley

[robwellesley]

I would try as follows:
config setprop ssmtpd InstancesPerIP xx
config setprop ssmtpd Instances xx (if to change that at all)
Michael

Michael is on the right track as the contents of...

/etc/e-smith/templates/var/service/sqpsmtpd/runenv

...shows.

Rob

[CharlieBrady]

smtpd=service
    Authentication=disabled
    Instances=60
    InstancesPerIP=5
... cut ...

I would try as follows:
config setprop ssmtpd InstancesPerIP xx
config setprop ssmtpd Instances xx (if to change that at all)

I'm rather curious as to why you would ever need more than 5 simultaneous SMTP connections per host.

[robwellesley]

smtpd=service
    Authentication=disabled
    Instances=60
    InstancesPerIP=5
... cut ...

I would try as follows:
config setprop ssmtpd InstancesPerIP xx
config setprop ssmtpd Instances xx (if to change that at all)

I'm rather curious as to why you would ever need more than 5 simultaneous SMTP connections per host.

As Michael says: config setprop ssmtpd Instances xx (if to change that at all)  This is not the 'problem' tho'.  The problem is that a mail server trying to connect to an SME mail server won't be bothered if it has to wait to deliver a mail.  However, a remote user delivering by ssmtp will get concurrency 'error' annoyances.

It's a pity we couldn't prioritise ssmtp connections, or can we?

[CharlieBrady]

I'm rather curious as to why you would ever need more than 5 simultaneous SMTP connections per host.

As Michael says: config setprop ssmtpd Instances xx (if to change that at all)  This is not the 'problem' tho'.  The problem is that a mail server trying to connect to an SME mail server won't be bothered if it has to wait to deliver a mail.  However, a remote user delivering by ssmtp will get concurrency 'error' annoyances.

My comment applies equally to ssmtp - why would you need more than 5 simultaneous ssmtpd connections?

It's a pity we couldn't prioritise ssmtp connections, or can we?

In what way would you want to prioritise them, and how would that help?

[robwellesley]

I'm rather curious as to why you would ever need more than 5 simultaneous SMTP connections per host.

As Michael says: config setprop ssmtpd Instances xx (if to change that at all)  This is not the 'problem' tho'.  The problem is that a mail server trying to connect to an SME mail server won't be bothered if it has to wait to deliver a mail.  However, a remote user delivering by ssmtp will get concurrency 'error' annoyances.

My comment applies equally to ssmtp - why would you need more than 5 simultaneous ssmtpd connections?

It's a pity we couldn't prioritise ssmtp connections, or can we?

In what way would you want to prioritise them, and how would that help?

More than 5 simultaneous ssmtpd connections?....
Ordinarily You wouldn't, would you? - you might if you had Outlook, etc. setup with multiple imap/pop3 email accounts tho.

In what way would you want to prioritise them...
Assume that ALL external ssmtpd connections will be from email clients, not other mail servers.  If the SME has reached it's (s)smtp concurrent limit the client may timeout.  A mail server trying to deliver mail to the SME can wait.  The roadwarrior may not be able to.

....and how would that help?  Quality of service.

[robwellesley]

....oh, and thanks for all your continued efforts on your great product.  If your ever down our way and needing a job....

[CharlieBrady]

More than 5 simultaneous ssmtpd connections?....
Ordinarily You wouldn't, would you? - you might if you had Outlook, etc. setup with multiple imap/pop3 email accounts tho.

I still don't see why you'd want more than 5 simultaneous connections from a single IP. Outlook will usually send only a single message (the one just composed) or will send multiple messages through a single connection (when cleaning the outbound queue).

In what way would you want to prioritise them...
Assume that ALL external ssmtpd connections will be from email clients, not other mail servers.  If the SME has reached it's (s)smtp concurrent limit the client may timeout.  A mail server trying to deliver mail to the SME can wait.  The roadwarrior may not be able to.

So I think what you are asking is that connections be accepted from some IP addresses, even after the "limit" has been reached. Sorry. There's no way to do that.

Are you sure that you have clearly separated total concurrency vs concurrency per IP in your mind?

[CharlieBrady]

....oh, and thanks for all your continued efforts on your great product.  If your ever down our way and needing a job....

Thanks, and thanks. There's many worse places one could be

[andy_wismer]

@CharlieBrady

A lot of Mail clients use more than one SMTP connection simultaenously, when using IMAP...

Thunderbird, Outlook, Outlook Express...

It all depends on the settings where copies of the message are stored. If, for example, sent mail should be stored on the server, more than one connection will be opened.

Actually, according to RFCs, only the IMAP Port should be used to handle messages, only outgoing messages are actually sent using SMTP. But maybe the developers of these products need to read the RFCs on IMAP a bit closer (or at all!).

My 2 Cts...

Andy Wismer