搜索 | 用户支持

防范以用户支持为名的诈骗。我们绝对不会要求您拨打电话或发送短信,及提供任何个人信息。请使用“举报滥用”选项报告涉及违规的行为。

详细了解

Maximum number of connections from user+IP exceeded ???

  • 3 个回答
  • 0 人有此问题
  • 1 次查看
  • 最后回复者为 matej.kovacic

more options

I'm using a VPN on my computer and phone and when I try to connect to the mail server, Thunderbird gives me an error saying that the mail server has disconnected. But when I disconnect from the VPN, everything works. This happens only with one mail server, on the others everything works OK even via VPN.

However, the the mail from this server is coming to my phone (where I use K-9 Mail).

I also tried to connect to the mail server via openssl, with the command "openssl s_client -connect mail.server.net:993 -crlf"

The connection is successful (when I'm on the VPN), but when I enter the command "a LOGIN my.username MYPASSWORD", it gives an error:

a NO [UNAVAILABLE] Maximum number of connections from user+IP exceeded (mail_max_userip_connections=20)

I have set the "Maximum Number of server connections to cache" to 1 in Thunderbird, I have set to check for mail every 12 minutes (it already was 15 minutes on the phone before), and it is still the same.

Any idea how to solve the issue? I am connecting to this server with the same username and from the same (VPN) IP only from my phone and my computer, so I find it really strange that there are more than 20 simultaneous connections...

I'm using a VPN on my computer and phone and when I try to connect to the mail server, Thunderbird gives me an error saying that the mail server has disconnected. But when I disconnect from the VPN, everything works. This happens only with one mail server, on the others everything works OK even via VPN. However, the the mail from this server is coming to my phone (where I use K-9 Mail). I also tried to connect to the mail server via openssl, with the command "openssl s_client -connect mail.server.net:993 -crlf" The connection is successful (when I'm on the VPN), but when I enter the command "a LOGIN my.username MYPASSWORD", it gives an error: a NO [UNAVAILABLE] Maximum number of connections from user+IP exceeded (mail_max_userip_connections=20) I have set the "Maximum Number of server connections to cache" to 1 in Thunderbird, I have set to check for mail every 12 minutes (it already was 15 minutes on the phone before), and it is still the same. Any idea how to solve the issue? I am connecting to this server with the same username and from the same (VPN) IP only from my phone and my computer, so I find it really strange that there are more than 20 simultaneous connections...

被采纳的解决方案

OK, found the problem!

My mail provider spotted a log entry saying "Multiple password values not supported".

Then things became clear. The problem was caused by Imunify360. So provider whitelisted my IP and suddenly everything started to work. :)

Anyway, it is still mystery to me why there were more than 20 IP+user connections... maybe a bug in Thunderbird?

定位到答案原位置 👍 0

所有回复 (3)

more options

If there is no error when not using the VPN, my guess would be the VPN has the limit to connections

有帮助吗?

more options

No, I have my own VPN - I tried Wireguard and OpenVPN, but on the same server, so I guess it is IP related, and it is caused by the mail server (that is not my own).

And besides, how could VPN be limiting connections, if I establish a TLS session (with openssl)? Connection is established, just at the authentication phase then fail. Again, authentication to mail server - encrypted connection - so VPN can not see the traffic.

I also checked how many TCP sessions are open from my VPN server to the mail server (with tcpdump) - and basically, it is just one from my computer.

有帮助吗?

more options

选择的解决方案

OK, found the problem!

My mail provider spotted a log entry saying "Multiple password values not supported".

Then things became clear. The problem was caused by Imunify360. So provider whitelisted my IP and suddenly everything started to work. :)

Anyway, it is still mystery to me why there were more than 20 IP+user connections... maybe a bug in Thunderbird?

有帮助吗?

我要提问

您需要登录才能回复。如果您还没账号,可以提出新问题