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robin24
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Dear Plesk users, server admins, forum guests and anyone else I forgot to mention,
I'd like to tell you all about an adventure I've had to go through up until today, the adventure of setting up the IMAP Mail service with Plesk and then actually being able to use it properly. Over all, it's all about some pretty limiting default values in a certain config file set by the Plesk installer, cupeled with the user being unable to see this from within the panel and to easily set more reasonable values.
But well, first things first. So, I installed Plesk 10.4.4 on a fresh installation of Debian Squeeze. Everything went through just fine, and I was able to access the Plesk Panel within minutes. All of the configuration went through just fine as well, up until when I got to the Mail server configuration (Postfix as the MTA and Courier for POP3 / IMAP access). Again, the actual configuration through Plesk went through just fine, and after adjusting the server-wide Mail settings and creating a Mailbox, I was pretty much set to go… Almost. After setting up the new EMail account in my Mail client (Apple Mail), I kept getting errors stating that Mail had been unable to establish a connection with the IMAP server. After restarting both the client and some server components a cowple times, it eventually worked, though not always. I wasn't happy with this situation at all, since it was far from being stable and reliable. Also, I was annoyed that I'd been unable to actually track down the issue - web Mail worked, connecting to IMAP via Telnet worked, there weren't any errors recorded in the logs. Also, I tried to get some help here in this forum and from my Plesk reseller, but with no luck at all. So then, at some point, I created a second EMail address and mailbox for another purpose. Again, I set up this account in Apple Mail. At this point, things were totally getting out of control. I now was unable to connect to the server at all, with the Mail client giving me errors saying that it was unable to connect to either of the two IMAP accounts. Thus, by setting up the second account, I had somehow locked myself out of the first account. Again, connecting to either of the 2 via Telnet worked without any problem, and I was really confused - no helpful entries in the logs then either. So then, at some point and after some major frustration, I came up with an idea. My idea was that, for some reason, maybe Courier would only accept a very low number of connections. I know that, in order to do mailbox caching and stuff, usual Mail clients establish around 5 connections to an IMAP server at a time. Since Plesk is often meant to run on huge servers with many types of clients, I had assumed that configuration parameters would be appropriately set to handle lots of traffic. However, after some looking around, I found the file /etc/courier-imap/imapd… And in there, I found this:
MAXDAEMONS=8
MAXPERIP=4
As can be seen here, the connection limit (MAXPERIP) value is even too low for even just one IMAP user running a Mail client that does mailbox caching. Thus, this is definitely *not* suitable for production use as long as you offer IMAP to end users or even just use it for yourself. I increased both MAXDAEMONS and MAXPERIP values, and now it's working just fine. So, a really easy solution for a really big and frustrating issue. Only thing is, I'm a bit annoyed at Parallels for A) setting such ridiculous values and B) not allowing the server admin to adjust this from within the panel. After all, I decided to go for Plesk because I want to do administrative tasks using a GUI rather than a shell, and so that I can pass along some of these tasks even to people who don't even know how to use a shell. Also, I don't like changing config files with this setup, as I'm afraid this could break some administrative Plesk features. However, as things are now, I can't really be sure if there are any other config problems like that, maybe even related to other services. Also, it's hard to decide how to tackle this issue. Am I supposed to go through every config file now to make sure there are no other such ridiculously small connection limits or anything like that?
I seriously hope you guys over at Parallels will address this issue, as it is so damn frustrating to track down for someone running a Mail server for the very first time. Yes, the solution turned out to be pretty trivial at the end, but I had to do so much tedious and unnecessary guesswork before I actually got to the issue. Please, can you just make this configurable from within the Panel, or at least increase the default values?
Thanks so much!!!
Robin
I'd like to tell you all about an adventure I've had to go through up until today, the adventure of setting up the IMAP Mail service with Plesk and then actually being able to use it properly. Over all, it's all about some pretty limiting default values in a certain config file set by the Plesk installer, cupeled with the user being unable to see this from within the panel and to easily set more reasonable values.
But well, first things first. So, I installed Plesk 10.4.4 on a fresh installation of Debian Squeeze. Everything went through just fine, and I was able to access the Plesk Panel within minutes. All of the configuration went through just fine as well, up until when I got to the Mail server configuration (Postfix as the MTA and Courier for POP3 / IMAP access). Again, the actual configuration through Plesk went through just fine, and after adjusting the server-wide Mail settings and creating a Mailbox, I was pretty much set to go… Almost. After setting up the new EMail account in my Mail client (Apple Mail), I kept getting errors stating that Mail had been unable to establish a connection with the IMAP server. After restarting both the client and some server components a cowple times, it eventually worked, though not always. I wasn't happy with this situation at all, since it was far from being stable and reliable. Also, I was annoyed that I'd been unable to actually track down the issue - web Mail worked, connecting to IMAP via Telnet worked, there weren't any errors recorded in the logs. Also, I tried to get some help here in this forum and from my Plesk reseller, but with no luck at all. So then, at some point, I created a second EMail address and mailbox for another purpose. Again, I set up this account in Apple Mail. At this point, things were totally getting out of control. I now was unable to connect to the server at all, with the Mail client giving me errors saying that it was unable to connect to either of the two IMAP accounts. Thus, by setting up the second account, I had somehow locked myself out of the first account. Again, connecting to either of the 2 via Telnet worked without any problem, and I was really confused - no helpful entries in the logs then either. So then, at some point and after some major frustration, I came up with an idea. My idea was that, for some reason, maybe Courier would only accept a very low number of connections. I know that, in order to do mailbox caching and stuff, usual Mail clients establish around 5 connections to an IMAP server at a time. Since Plesk is often meant to run on huge servers with many types of clients, I had assumed that configuration parameters would be appropriately set to handle lots of traffic. However, after some looking around, I found the file /etc/courier-imap/imapd… And in there, I found this:
MAXDAEMONS=8
MAXPERIP=4
As can be seen here, the connection limit (MAXPERIP) value is even too low for even just one IMAP user running a Mail client that does mailbox caching. Thus, this is definitely *not* suitable for production use as long as you offer IMAP to end users or even just use it for yourself. I increased both MAXDAEMONS and MAXPERIP values, and now it's working just fine. So, a really easy solution for a really big and frustrating issue. Only thing is, I'm a bit annoyed at Parallels for A) setting such ridiculous values and B) not allowing the server admin to adjust this from within the panel. After all, I decided to go for Plesk because I want to do administrative tasks using a GUI rather than a shell, and so that I can pass along some of these tasks even to people who don't even know how to use a shell. Also, I don't like changing config files with this setup, as I'm afraid this could break some administrative Plesk features. However, as things are now, I can't really be sure if there are any other config problems like that, maybe even related to other services. Also, it's hard to decide how to tackle this issue. Am I supposed to go through every config file now to make sure there are no other such ridiculously small connection limits or anything like that?
I seriously hope you guys over at Parallels will address this issue, as it is so damn frustrating to track down for someone running a Mail server for the very first time. Yes, the solution turned out to be pretty trivial at the end, but I had to do so much tedious and unnecessary guesswork before I actually got to the issue. Please, can you just make this configurable from within the Panel, or at least increase the default values?
Thanks so much!!!
Robin
