I had a strange email problem the other day. Support has solved the problem but I thought it sounded interesting so I wanted to mention it here.
I was testing my ability to send email via JH’s SMTP server. I could send to many different domains, including hotmail.com. But when I sent to yahoo.com I got an error message from the JH SMTP server that said something to the affect of user does not exist.
After opening a ticket (and remember, this has been solved by support, but they didn’t tell me what the problem actually was) I got to thinking about it. I am thinking that someone setup a domain of “yahoo.com” into their control panel. This would cause JH’s DNS servers to think that anything going to yahoo.com goes right here on their own mail server. And if the JH mail servers are setup to use the JH DNS servers, then you would see this exact problem.
This is all theory. I don’t know what the problem was. In any case, this brings up the question of whether JH should be using their own DNS servers to operate their production systems. Its nice for testing before your domain goes live, but I would think that all production systems should use a standard DNS server, one from their ISP for example, not an “authoritative” DNS.
Just a thought. I don’t know a lot about this stuff, but thought I’d bring it up for a geek discussion.
Your theory is right, except that only that mailbox would be refused, not all yahoo. Also, it would be best if we dont give people bad ideas…if you know what I mean
Yet, I have seen this error when the mailbox on the other side is full up, I and think it’s more likely.
[QUOTE=Underdog]
Your theory is right, except that only that mailbox would be refused, not all yahoo. Also, it would be best if we dont give people bad ideas…if you know what I mean
Yet, I have seen this error when the mailbox on the other side is full up, I and think it’s more likely.
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No, I think it would be all mail going to that domain. If Jodo’s SMTP servers are using their DNS servers, and someone setup a domain here by the name of Yahoo.com, then Jodo’s SMTP servers would send the mail to Jodo’s mail servers… Jodo’s mail servers would reject unless you send to a valid email account that this Jodo user setup in their control panel.
You can test this by setting up a domain that is not registered anywhere. Set it up in your control panel. Setup a mailbox, etc. Then sent mail using the JH SMTP server. It will be sent and received, even though the domain you setup isn’t a real domain, registered anywhere other than on the JH DNS servers.
I was sending test messages to my Yahoo account and it is not full, so I’m sure that wasn’t the issue.
[QUOTE=Homer]
No, I think it would be all mail going to that domain. If Jodo’s SMTP servers are using their DNS servers, and someone setup a domain here by the name of Yahoo.com, then Jodo’s SMTP servers would send the mail to Jodo’s mail servers… Jodo’s mail servers would reject unless you send to a valid email account that this Jodo user setup in their control panel.
You can test this by setting up a domain that is not registered anywhere. Set it up in your control panel. Setup a mailbox, etc. Then sent mail using the JH SMTP server. It will be sent and received, even though the domain you setup isn’t a real domain, registered anywhere other than on the JH DNS servers.
I was sending test messages to my Yahoo account and it is not full, so I’m sure that wasn’t the issue.
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I had this happen to me once with a client and it messed up the whole domain… not just one mailbox. BUT as stated it only messed it up for folks on using that host’s dns services. Everyone outside of that host worked find.
[QUOTE=gsaunders]
I had this happen to me once with a client and it messed up the whole domain… not just one mailbox. BUT as stated it only messed it up for folks on using that host’s dns services. Everyone outside of that host worked find.
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Yes, you’re right. I must have misunderstood your original statement. It would affect anyone using that DNS server. In this case it would be most of JH’s customers.
My main thought was that JH should not be using their own DNS servers for production mail servers. They should be using what the rest of the world uses.
Please, dont give people any bad ideas on an open forum.
I think it?s worth discussing the issue…but on another instance…cause you dont want to hype people?s curiosity.
Basically, you?re shooting your own foot this way.
Perhaps you should demand some explanation via e-mail or TT. And I would love to be posted on a Private Message whatever you find out.
[SIZE=2]TO THE MODERATOR[/SIZE]: To avoid a worse case scenario, I ask some moderator to move this post to a more private place, like Customers Only Forum, or whatever.
Thank you
I never gave it much thought, but you’re right. Different nameservers should be used, but even then it depends on the exact configuration of the mailserver itself. If it isn’t properly shielded, it would be simple to create catchall mailservices for hotmail, gmail, etc and intercept mail being sent there :rolleyes:
[QUOTE=SubSpace]
I never gave it much thought, but you’re right. Different nameservers should be used, but even then it depends on the exact configuration of the mailserver itself. If it isn’t properly shielded, it would be simple to create catchall mailservices for hotmail, gmail, etc and intercept mail being sent there :rolleyes:
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Yes. They should use different DNS servers on production systems.
[QUOTE=Underdog]
Homer,
Please, dont give people any bad ideas on an open forum.
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I see your point, but not talking about it doesn’t solve the problem. The real solution is to use a real production DNS server on the production systems.
I have no problem with JH moving or deleting this thread. I hope I made my point and in the end helped JH and its customers by pointing out this problem. I’m not a network engineer so all I can do is hope that JH will do whatever the right things is to correct this problem.
Rest assured, if anyone exploits something like this, he will be caught pretty quickly and would have commited a serious crime (something we would definately report).
