SMTP Access Denied

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sagelike
Posts: 288
Joined: Fri Feb 23, 2007 4:58 am

SMTP Access Denied

Post by sagelike » Mon Nov 26, 2018 7:13 pm

Hi there,

I've run into tough problem were a client who recently had to replace router is being denied SMTP access to our server from their office location.

Telnet returns same result from their office: 'denied access at...'

- I've checked IP blocks in ME and there IP does not appear
- Users can SMTP outside the office.
- I removed Spamhaus from Blacklist filters.
- Their external IP does not appear on any blacklists.

My question is, where in the logs can I find their connection failure? I've looked and can't find anything to help me find the problem.

I'm certain this is routing issue of some kind on their end but I can't prove it. No one else has this issue.

My guess is that they are somehow resolving from their internal IP though external tests show that to not be the case.

Any insight would be greatly appreciated.

Thanks
G

sagelike
Posts: 288
Joined: Fri Feb 23, 2007 4:58 am

Re: SMTP Access Denied

Post by sagelike » Thu Nov 29, 2018 9:34 pm

Bump

Brett Rowbotham
Posts: 535
Joined: Mon Nov 03, 2003 7:48 am
Location: Cape Town

Re: SMTP Access Denied

Post by Brett Rowbotham » Fri Nov 30, 2018 4:20 am

Try, from their office, telnet <your ip> 80 (assuming you are running a web server) to check if the block is actually from ME or from some firewall setting on their side.

(Note that the telnet connection is not supposed to actually work, you should just get a HTTP 400 response)

sagelike
Posts: 288
Joined: Fri Feb 23, 2007 4:58 am

Re: SMTP Access Denied

Post by sagelike » Fri Nov 30, 2018 6:42 pm

Thanks Brett. I'll give that a try.

I have tried telnet to port 25 and 587 and I do get a 'Mailenable Service....Denied Access' response.

Brett Rowbotham
Posts: 535
Joined: Mon Nov 03, 2003 7:48 am
Location: Cape Town

Re: SMTP Access Denied

Post by Brett Rowbotham » Mon Dec 03, 2018 4:51 am

If you are already getting the MailEnable denied message, which was not mentioned in your original post, then the connection is not being blocked on their side so you need to find the log file that will say why the block was being made.

maxel91
Posts: 62
Joined: Sat Dec 10, 2016 1:10 am

Re: SMTP Access Denied

Post by maxel91 » Mon Dec 03, 2018 8:58 pm

Hi, for the problem see here:

Image

sagelike
Posts: 288
Joined: Fri Feb 23, 2007 4:58 am

Re: SMTP Access Denied

Post by sagelike » Wed Jan 09, 2019 6:48 pm

Brett Rowbotham

Which log files would show that?

thx
Glenn

Brett Rowbotham
Posts: 535
Joined: Mon Nov 03, 2003 7:48 am
Location: Cape Town

Re: SMTP Access Denied

Post by Brett Rowbotham » Thu Jan 10, 2019 4:53 am

Generally the SMTP activity/debug log files will have all the information about connections successful or otherwise.

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