Il 10/07/19 10:20, Aki Tuomi ha scritto:

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On 12/06/2019 20:02 Paolo Daniele via dovecot <dovecot@dovecot.org> wrote:

Hi, i've a question for you. I've two dovecot imap/pop server behind a zen load balancer. Load balancing is made by lx4nat so the public ip address of my load balancer contact directly the dovecot servers. Since few months i've a message from thunderbird that i've reached the imap limit login for ip. I've triend to increase the max user ip parameter but sometimes i've the same problem. It's a strange things that actually i'm able to mitigate by reduce the number of cached connections in Thunderbird but it's not normal. What do you think about that? Maybe there's some tuning that you can suggest. Thank you, Paolo

Have you ensured, by checking logs, that the connections are seen by dovecot to come from public IP addresses?

Also, thunderbird is known to open lots of concurrent connections.

Aki Yes, connections are coming from the ip address of load balancer (also checked with a netstat -an) I know that thunderbird has this problem and i haven't problem since the numbers of email domain increase. I'm not sure the impact of rising the max user ip to an higher value in terms of ram consumption and cpu Any suggestion? Thanks for your answer! Paolo

-- Paolo Daniele E-mail: paolo.daniele@tlcweb.it Intendo s.r.l. Mobile: +39 388 9887357 Business Unit TLCWEB Tel.: +39 0968 430786 Via Coschi, 11 Skype: paolo_daniele1 88046 - Lamezia Terme, Cz Web: http://www.tlcweb.it Italia Web: http://www.intendo.it

Il 10/07/19 10:27, Aki Tuomi ha scritto:

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On 10/07/2019 11:24 Paolo Daniele via dovecot <dovecot@dovecot.org> wrote:

Il 10/07/19 10:20, Aki Tuomi ha scritto:

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On 12/06/2019 20:02 Paolo Daniele via dovecot <dovecot@dovecot.org> wrote:

Hi, i've a question for you. I've two dovecot imap/pop server behind a zen load balancer. Load balancing is made by lx4nat so the public ip address of my load balancer contact directly the dovecot servers. Since few months i've a message from thunderbird that i've reached the imap limit login for ip. I've triend to increase the max user ip parameter but sometimes i've the same problem. It's a strange things that actually i'm able to mitigate by reduce the number of cached connections in Thunderbird but it's not normal. What do you think about that? Maybe there's some tuning that you can suggest. Thank you, Paolo

Have you ensured, by checking logs, that the connections are seen by dovecot to come from public IP addresses?

Also, thunderbird is known to open lots of concurrent connections.

Aki Yes, connections are coming from the ip address of load balancer (also checked with a netstat -an) I know that thunderbird has this problem and i haven't problem since the numbers of email domain increase. I'm not sure the impact of rising the max user ip to an higher value in terms of ram consumption and cpu Any suggestion? Thanks for your answer! Paolo

What's your current limit? The default value is 100.

Aki Actually:

mail_max_userip_connections = 500

Thanks, Paolo

-- Paolo Daniele E-mail: paolo.daniele@tlcweb.it Intendo s.r.l. Mobile: +39 388 9887357 Business Unit TLCWEB Tel.: +39 0968 430786 Via Coschi, 11 Skype: paolo_daniele1 88046 - Lamezia Terme, Cz Web: http://www.tlcweb.it Italia Web: http://www.intendo.it

Il 10/07/19 10:27, Sami Ketola ha scritto:

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On 10 Jul 2019, at 11.24, Paolo Daniele via dovecot <dovecot@dovecot.org> wrote:

connections are coming from the ip address of load balancer (also checked with a netstat -an) I know that thunderbird has this problem and i haven't problem since the numbers of email domain increase. I'm not sure the impact of rising the max user ip to an higher value in terms of ram consumption and cpu Any suggestion? At some point in time thunderbird opened 1 connection per email folder on destination. So if you have 20 folders thunderbird would open 20 connections. Not sure if it is still true with current thunderbird versions.

There is a limit on thunderbird config that controls this.

Sami

I've checked the limitation on thunderbid and i've mitigated on our pcs (which have multiple email configured on the same servers) by telling thunderbird to store only one connection at the same time. But i cannot "force" or contact every customer to check what client they use and change :) This also create problems with Roundcube webmail which sometimes give me the same error. Paolo

-- Paolo Daniele E-mail: paolo.daniele@tlcweb.it Intendo s.r.l. Mobile: +39 388 9887357 Business Unit TLCWEB Tel.: +39 0968 430786 Via Coschi, 11 Skype: paolo_daniele1 88046 - Lamezia Terme, Cz Web: http://www.tlcweb.it Italia Web: http://www.intendo.it

Le 10 juil. 2019 à 10:24, Paolo Daniele via dovecot <dovecot@dovecot.org> a écrit :

Il 10/07/19 10:20, Aki Tuomi ha scritto:

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On 12/06/2019 20:02 Paolo Daniele via dovecot <dovecot@dovecot.org> wrote:

Hi, i've a question for you. I've two dovecot imap/pop server behind a zen load balancer. Load balancing is made by lx4nat so the public ip address of my load balancer contact directly the dovecot servers. Since few months i've a message from thunderbird that i've reached the imap limit login for ip. I've triend to increase the max user ip parameter but sometimes i've the same problem. It's a strange things that actually i'm able to mitigate by reduce the number of cached connections in Thunderbird but it's not normal. What do you think about that? Maybe there's some tuning that you can suggest. Thank you, Paolo

Have you ensured, by checking logs, that the connections are seen by dovecot to come from public IP addresses?

Also, thunderbird is known to open lots of concurrent connections.

Aki Yes, connections are coming from the ip address of load balancer (also checked with a netstat -an)

If connection are seen as coming from the IP address of the load balancer, isn't it normal that dovecot complains ? That means that dovecot sees all connections as coming from a single client, which would explain why you reach that limit.

Le 10 juil. 2019 à 11:46, Paolo Daniele <paolo.daniele@tlcweb.it> a écrit :

Il 10/07/19 11:44, Jean-Daniel Dupas ha scritto:

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Le 10 juil. 2019 à 10:24, Paolo Daniele via dovecot <dovecot@dovecot.org> a écrit :

Il 10/07/19 10:20, Aki Tuomi ha scritto:

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On 12/06/2019 20:02 Paolo Daniele via dovecot <dovecot@dovecot.org> wrote:

Hi, i've a question for you. I've two dovecot imap/pop server behind a zen load balancer. Load balancing is made by lx4nat so the public ip address of my load balancer contact directly the dovecot servers. Since few months i've a message from thunderbird that i've reached the imap limit login for ip. I've triend to increase the max user ip parameter but sometimes i've the same problem. It's a strange things that actually i'm able to mitigate by reduce the number of cached connections in Thunderbird but it's not normal. What do you think about that? Maybe there's some tuning that you can suggest. Thank you, Paolo

Have you ensured, by checking logs, that the connections are seen by dovecot to come from public IP addresses?

Also, thunderbird is known to open lots of concurrent connections.

Aki Yes, connections are coming from the ip address of load balancer (also checked with a netstat -an) If connection are seen as coming from the IP address of the load balancer, isn't it normal that dovecot complains ? That means that dovecot sees all connections as coming from a single client, which would explain why you reach that limit.

Yeah of course, but i've checked that i haven't reach the max_user_per_ip limit by counting dovecot process coming from that ip address. So the strange and the reason why i'm writing to you :)

Don't know if this is still relevant in your dovecot version, but did you see this:

https://serverfault.com/questions/385187/dovecot-ignoring-maximum-number-of-... <https://serverfault.com/questions/385187/dovecot-ignoring-maximum-number-of-imap-connections>

People had some issue by using the mail_max_userip_connections in the imap section and had to set it in the global section instead.