Linux - GeneralThis Linux forum is for general Linux questions and discussion.
If it is Linux Related and doesn't seem to fit in any other forum then this is the place.
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Introduction to Linux - A Hands on Guide
This guide was created as an overview of the Linux Operating System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter.
For more advanced trainees it can be a desktop reference, and a collection of the base knowledge needed to proceed with system and network administration. This book contains many real life examples derived from the author's experience as a Linux system and network administrator, trainer and consultant. They hope these examples will help you to get a better understanding of the Linux system and that you feel encouraged to try out things on your own.
Click Here to receive this Complete Guide absolutely free.
My problem is that i am not receiving ndrs when a message is undeliverable. For example, when the email address is invalid.
This is the way my mail flows:
Client >> Exchage 2003 server >> Redhat Sendmail Server >> Internet
Internet >> Redhat Sendmail >> spam filter >> exchange
My sendmail server just acts as a relay. We have the mailertable setup to foward any mail for our domain. we are using spam cop to filter through some of the mail before its forwarded internally. And other than that were not doing anything fancy.
When I send a message to an invalid external address I see an error in the maillog stating user unknown. Yet I never receive an undeliverable message. So I started to troubleshoot this by sending to an invalid address then searching the maillogs for my email address to see if an ndr was sent back. I found no trace of any messages going back to my address. So then I went to my yahoo account and sent an email to the same invalid address and immediatly recieved an ndr.
This system has been online for some time now so I don't know if someone purposely configured it to not send ndrs. Please let me know if you have any ideas on where I should begin to investigate this issue.