SMTP connection timeout configuration in AwareIM

zrinyi

Hi everyone,

I’m currently investigating an SMTP email sending delay issue in one of our AwareIM applications and I would like to ask whether there is any way to configure the SMTP connection timeout parameters in AwareIM / BAS Server.

What we are experiencing:

the application sends emails successfully,
however, actual delivery is sometimes significantly delayed,
during network testing we discovered that the SMTP hostname resolves to multiple IP addresses,
some of those IPs are not reachable from our server,
therefore JavaMail seems to try several failed connections before finally finding a working SMTP endpoint.

We already identified this as a network / SMTP connectivity issue rather than an AwareIM business logic issue.

At the moment I am looking specifically for a way to reduce the SMTP connection timeout values, for example:

mail.smtp.connectiontimeout
mail.smtp.timeout
mail.smtp.writetimeout

Questions:

Is there any officially supported way to configure JavaMail SMTP timeout parameters in AwareIM?
Can these JVM properties be added through awareim.conf or another configuration file?
Has anyone already implemented a similar workaround successfully?

Any advice or best practices would be greatly appreciated.

Thanks!
István

joben

Is it a fixed amount of different multiple IP addresses that the hostname resolves to?

Like:

10.20.30.40
10.20.30.41
10.20.30.42

You could edit your hosts file on the server so that the name always resolves to the IP that works for you.

This could buy you some time to speed up the deliveries until you have successfully troubleshooted the networking issues. I don’t really recommend to make such changes in the hosts file, as it can really complicate troubleshooting in the future should you forget your manual changes.

zrinyi

Yes, exactly. The hostname resolves to multiple IP addresses and only some of them are reachable from our server.

For example:

185.136.64.11 → reachable
185.136.64.10 → connection timeout
185.136.65.11 → connection timeout

Because of this, JavaMail appears to try unreachable endpoints first and only later succeeds with a working SMTP node, which explains the email sending delays we are seeing.

For now I will probably use a temporary workaround (fixed IP / hosts override) until the networking issue is properly resolved.

Thanks for the confirmation and advice!