QTSMTPCLTD High CPU Percentage

[rmullis]

For the last two days, the email from our RPG programs and PHP application have stopped sending. I can stop SMTP and restart it and one maybe two emails will go through and then it will stop again. I noticed that job QTSMTPCLTD is constantly running and usually with a high CPU percentage (usually 80% or better). I have looked in the joblog and see no messages that may indicate an error. There also seems to be a large number of QTSMTPCLTP prestart jobs running. I have never noticed there being a large number of these jobs before.

Does anyone have any suggestions why this may be happening? Please pardon my ignorance on this subject. I am a novice when it comes to SMTP and TCP, etc.

FYI, my SMTP mail router address is 10.1.1.14, but I have also tried using smtp.gmail.com, which is the SMTP server for our hosted email from Google, with the same results.

[rmullis]

Re: QTSMTPCLTD High CPU Percentage

I have discovered from command NETSTAT that as soon as I start SMTP a large number of outside IP addresses connect to our system through SMTP. When I do a lookup on several of the strange IP addresses, they show as being in Taiwan. Apparently, we have spammers trying to use our system to forward email. So now my question becomes, how do I prevent outside systems from using our system to forward emails or connecting to SMTP on our system? I have SMTP on our system to "Allow relayed email" = *NONE.

[littlepd]

Re: QTSMTPCLTD High CPU Percentage

I am not an expert on this topic, but I do have a little experience.

Am I correct in my assumption that you only want to use the SMTP server to send mail from within your domain? if so, can you set up your firewall to block inbound traffic to the SMTP server's IP?