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Hi, I was trying to send email to an account hosted on Office 365 from a different server. My SMTP server follows all the best practices: PTR record (fuse.onezerone.com), SPF (onezerone.com), etc.
However, I just received an error that says my IP address [18.104.22.168] is on a blacklist. I went to the Spamhaus site and my IP is NOT listed.
I’ve also used MXToolbox http://www.mxtoolbox.com/SuperTool.aspx?action=blacklist%3a22.214.171.124# and it shows that my IP is NOT on any of the 95 blacklists it monitors.
It is vital that I’m able to send email to our accounts on Office 365 from my SMTP/Web server. Our web application sends email notifications to users with Office 365 accounts.
08/21/12 14:54:25 126.96.36.199 EHLO fuse.onezerone.com 250-CO1EHSMHS013.bigfish.com Hello [188.8.131.52]
08/21/12 14:54:25 184.108.40.206 MAIL FROM:<email@example.com> SIZE=4822 250 2.1.0 Sender OK
08/21/12 14:54:25 220.127.116.11 RCPT TO:<firstname.lastname@example.org> 550 5.7.1 Service unavailable; Client host [18.104.22.168] blocked using Spamhaus Blocklist, mail from IP banned; To request removal from this list see http://www.spamhaus.org/query/bl?ip=22.214.171.124
08/21/12 14:54:25 126.96.36.199 QUIT 221 2.0.0 Service closing transmission channel
Hi Aaron, it looks like the issue was temporary. I checked my logs and there were not more blocked emails, even from the server at 188.8.131.52.
Thanks again for your assistance.
Hi Aaron, thanks for replying.
Let me answer your questions:
1) No, this was not an error that I received in email. My web app tried to send me a notification. I did not receive it, so I looked at the SMTP server logs and that is where I found the block. For some reason, my SMTP service did not send me an NDR. It never successfully sent the email to my Office 365 mailbox. It was blocked by the server CO1EHSMHS013.bigfish.com [184.108.40.206].
2) Yes, the server CO1EHSMHS013.bigfish.com replied with 550 5.7.1 Service unavailable; Client host [220.127.116.11] blocked using Spamhaus Blocklist, mail from IP banned; To request removal from this list see www.spamhaus.org/.../bl.
However, when I clicked the link for Spamhaus, it said my IP address was NOT listed.
3) No, my SMTP server is not an open relay. It is simply a local SMTP service designed to send email notifications from our web app. I have configured the SPF records to list this IP as a valid sender: "v=spf1 include:outlook.com a:fuse.onezerone.com ~all"
The only NDR that I received was when I was trying to send an email to email@example.com and firstname.lastname@example.org about this issue. It is odd that you don't have a standard postmaster email to report these types of problems to.
Anyway, that's about all the information I can provide. Like I said, this just started happening yesterday. Thanks for your assistance.
Yes, this just started happening. And it doesn't happen with all notifications, so it looks like some servers are using an invalid blacklist.
I looked through my logs and it appears that there is one server on your end that is blocking my emails. The rest appear to go through just fine:
The IP address of the blocking server is 18.104.22.168.
These IP addresses work just fine:
The sender email is email@example.com which is from our web app. It's also an alias on my main account firstname.lastname@example.org.
We are on the P1 plan, so an inbound rule does not apply to us.
Anyway, if you could have one of your engineers look into why 22.214.171.124 erroneously thinks we're on the Spamhaus blacklist, that would be great.
How are things going now?Do you need more assistant about this issue?
I’m glad to hear that the issue has been resolved. Thanks for your update. Thanks,Aaron Yuan