421 Service Not Available -37, Trouble with smtp traffic to xmail 1.24

Hi All,

we use xmail 1.24 as mail relay for about 10 smtp domains.

Now we recognized a lot of "421 [XMail 1.24 ESMTP Server] service not available (-37), closing transmission channel" messages as we tried to troubleshoot undeliverable e-mails to our xmail server.

I tried a lot with the server.tab and the smtp.ipprop.tab.
I disabled CheckSenderDomain, tried with allow null sender but nothing
changed.

I cant find any informations what -37 means. I hope someone can help me.

Thanks in advance for your assistant.

PS: This is my server.tab

"RootDomain" "changed.net"
"SmtpServerDomain" "changed.net"
"POP3Domain" "changed.net"
"HeloDomain" "changed.net"
"PostMaster" "postmaster@changed.de"
"RemoveSpoolErrors" "1"
"NoSenderBounce" "1"
"MaxMTAOps" "16"
"ReceivedHdrType" "0"
"SMTP-TLS" "0"
"EnableCTRL-TLS" "0"
"EnableSMTP-TLS" "0"
"EnablePOP3-TLS" "0"
"SmtpMsgIPBanSpammers" "550 Denied due inclusion of your IP in our spamlists"
"SmtpMsgIPBanSpamAddress" "550 Denied due inclusion of your email address in our spam lists"
"SmtpMsgIPBanMaps" "550 Denied due inclusion of your IP in the following map"
"CustomSMTPMessage" "Please open http://www.bitminder.de to get more information about this error"
"NotifySendLogToSender" "0"
"MaxMessageSize" "100000"
"EnableAuthSMTP-POP3" "1"
"AllowNullSender" "0"
"SMTP-MaxErrors" "2"
"SmtpMinDiskSpace" "100000"
"CheckMailerDomain" "0"
"DefaultSmtpPerms" "MR"

#"ErrorsAdmin" "root@xmailserver.test"
#"TempErrorsAdmin" "send-failures@xmailserver.test"
#"DefaultSMTPGateways" "192.168.1.2,192.168.1.15"
#"DisableEmitAuthUser" "1"
#"NotifyMsgLine***tra" "8"
#"NotifySendLogToSender" "0"
#"NotifyTryPattern" "1"
#"FetchHdrTags" "+//0-Deliver-To,+Received,To,Cc"
#"Pop3SyncErrorAccount" "psync-errors@xmailserver.test"
#"AllowSmtpVRFY" "1"
#"AllowSmtpETRN" "1"
#"SmtpMinVirtMemSpace" "64000"
#"Pop3MinVirtMemSpace" "64000"
#"CustMapsList" "list.dsbl.org.:1,blackholes.mail-abuse.org.:1,dialups.mail-abuse.org.:0"
#"SMTP-RDNSCheck" "1"
#"SmartDNSHost" "dns.home.bogus.net:tcp,192.168.1.1:udp"
#"DynDnsSetup" "www.dns4ever.com,80,/sys/u.cgi?d=MYDOMAIN&u=MYUSERNAME&p=MYPASSWORD&i=%s"
#"DynDnsSetup"
#"SmtpConfig" "mail-auth"
#"SmtpConfig-192.168.0.1" "mail-auth"
#"members.dyndns.org,80,/nic/dyndns?action=edit&started=1&hostname=YES&host_id=yourhost.ourdomain.ext&myip=%s&wildcard=OFF&mx=mail.exchanger.ext&backmx=NO,foouser,foopasswd"

This error is defined as

Looks like your DNS cannot not resolve the peer's hostname.

Hi Harald,

thank you very much for your answer. I checked the name resultion on the
system. It seems that only remote systems without a RDNS entry got this
SMTP Message.

I use the smtp.ipprop.tab and the smtp.hnprop.tab to grant
some systems with no rdns access to the xmail server. I read in the
xmail documentation that if the smtp.hnprop.tab exist xmail does a
RDNS Lookup to. So i removed the smtp.hnprop.tab an the errors
are gone.

Now a sending smtp server with no rdns record registerd got the smtp
message "551 Server access forbidden by your IP" and this is for my
understanding the correct resonse. I do not realy understand why the
existens of the smtp.hnprop.tab causes xmailer to generate the 421
Service Not Available (-37) message in my setup but anyway
xmail is up and running as it was the last years.

Thanks again for your great hint!

Yours, Mike

Good to see you trackling this down so fast

>I do not realy understand why the existens ...
Must be some issue with its content ...

Maybe you can help out with this I was having the same error so i removed the smtp.hnprop.tab and the server ran fine for a night now I am getting constant errors generated by xmail saying:

The description for Event ID ( 0 ) in Source ( xmail ) cannot be found. The local computer may not have the necessary registry information or message DLL files to display messages from a remote computer. You may be able to use the /AUXSOURCE= flag to retrieve this description; see Help and Support for details. The following information is part of the event: Server too busy, retry later (POP3 thread count)
.

In the meantime no one can send mail whatsoever. Plz help

This is my command line:
-Pp 110 -Pt 300 -Pl -Pw 240 -PX 30 -Sp 25 -St 300 -Sl -SX 30 -Sr 100 -Qn 30 -Qt 38 -Qi 5 -Ql -Cp 6017 -Cl -CX 2 -Ln 110 -Ll

Hello Zanderi,

Each program or service that logs events to the event logs, needs to provide a set of registry settings that point to the location of the dll files that are used to decode the event log messages. As i know xmail does not provide such informations but anyway have you tried to increase the value for conccurent pop3 sessions on
your xmailer.

You have configured 30 concurent sessions (-PX 30) and a timeout value for each session of (-PT 300). Try to increase the -PX value or decrease the -PT value.

If you have for e.g. 100 POP3 users an they check their mailboxes every 5 minutes
a vlaue of -PX 30 could be to less.

You can use a network monitoring tool like wireshark to monitor this type of connections.

Hope that helps.