Gradual degradation of service?

#1

Customer for just over a month. 2 x domains (purchased from Namesilo, DNS by Cloudflare). All working for about 2 weeks now I notice Nextcloud file hosting constantly logging out my Android & Linux clients, Android Calendar/Contacts starting to fail to sync and now Android email client (Fairmail) reporting connection failures “Maximum number of IP’s exceeded”. Im on Arrow server which seems to geolocate to Germany. I’m in Asia Pacific (NZ, 1Gb Fiber, Business grade ISP).

I have understood from the beginning that NC was a freebie add-on. I’m in the process of abandoning the MXroute NC hosting for a reliable service elsewhere.

Anyone at MXroute have a comment on Android email client ‘Fairmail’ reporting connection failure “Maximum numbers of IP’s exceeded”?

My inexpert understanding - I could be wrong - is this message derives from a server rate limit. Considering both my domains are only very low volume personal mail this doesn’t bode well for the reliability of the mail service either. Pending any response I’m beginning to look for a more reliable host to transfer to…

#2

I’ve increased the limit to 60 on the Arrow server, but it is noteworthy that no one else had been hitting the 30 open IMAP connection limit previously. This can be caused by a faulty email client that isn’t properly closing connections. Upon review of your specific case, it seems to be opening tens of connections every minute, and then they’re timing out 180 seconds later due to inactivity rather than disconnecting properly. This may mean that you might hit the limit unless I raise it to unsafe numbers while using that email client if it isn’t repaired.

As for NextCloud, hardware is ordered to move it closer to the Crossbox master which is working as the imap proxy for login. This should, in theory, improve it’s performance and reliability. The hardware is a bit delayed right now due to covid-19 supply chain hits. I’ll continue to refrain from advertising this as a major feature until I’m confident that it’s resolved.

#8

Hi

Thanks for quick reply.
Looks good this end!
Thanks for your help!

Stu

#3

Thank you Jarland. Regarding NC - I understand the situation. Regarding rate limits we have narrowed it down to one specific Android email client and will follow it up with the developer. Cheers mate.

#4

Follow up : Checking the Fairmail Github reveals this is a known problem caused by ‘Synchronising’ lots of email ‘folders’ (probably occurs in other highly configarable email clients also. The dev claims Gmail has a rate limit of 15 connections).

I will turn off sync of these folders or reduce them to polling no more than hourly. That should stop the problem. I see no reason to leave the rate limit at 60 as I has taken action to prevent the problem.

As for Nextcloud, charging a modest, commercially realistic add-on fee for this functionality would welcome.

Cheers and thank you for your extemly quick assistance.

#6

Message me on chat.mxroute.com with the connecting IP and I’ll grep the logs for you. If it’s checking every 20 seconds and not properly closing the connection, it very well may be hitting limits.

Note: chat.mxroute.com uses the same login as portal.mxroute.com.

#5

Hi
I have an app that checks our email (imap) account every 20 secs and it looks like it is hitting a limit somewhere, which could be what you are discribing here. I’m also on arrow.
Each connection is disconnected everytime (as far as I can tell) and it is possible two scripts could run at the same time (I’m working on stopping that).
How can I tell if I’m hitting a limit of “checking” the account?
It is taking about 25secs just to connect but earlier in the day it is a second or two (hense why I think I am hitting a limit).
If I try the script on gmail it is fast (1sec).

Thanks in advance! :slight_smile:
Stu

#7

Actually, in update to my last reply, I found that Arrow was hitting process_limit and while Dovecot is unclear about which process limit it is, I think I’ve resolved it. Monitoring for further issues.