SMTP (port 25) outgoing connections blocked

1

I cannot make outgoing connections on port 25 from my EC2 instance. I have filed the "removal of port 25 throttling" form twice now, but I am still not able to make outgoing connections on port 25. My security group allows all outgoing ports, and my instance's internal firewall is clear. Is anyone else experiencing this? I cannot find any explicit mention of a policy saying that AWS blocks port 25. All of my connection attempts fail -- this is not a matter of throttling, but rather a complete block.

Seva
已提問 5 年前檢視次數 6047 次
9 個答案
1

I am also struggling to get AWS to open TCP port 25 outbound for me. My request received this response:

This account, or those linked to it, have been identified as having at least one of the following:
* A history of violations of the AWS Acceptable Use Policy
* A history of being not consistently in good standing with billing
* Not provided a valid/clear use case to warrant sending mail from EC2

Bullet points 1 and 2 are not the case, so it seems AWS didn't like my use case, which is that I am an IT professional and run a very low volume personal email server, both to keep my knowledge current and to keep my personal communication out of the hands of large corporations. AWS has now not only denied my request, but they stated this:

We cannot assist you further with this issue and we may not respond to additional messages on this subject.

I'm at a loss for words. Is there any way to talk to a live person at AWS about this? If my use case is not valid I can't imagine what they would consider valid. I have spent weeks of effort setting up infrastructure at AWS. Was that all really for nothing?

已回答 3 年前
  • 2 years later, they are doing exactly the same to me, with the exact same explanation....

1

Hello,

I have checked your account and I could see that you have one running Ubuntu based instance in the us-east-1 region. I can confirm that there is no TCP port 25 throttle placed on this instance. Neither there are any rules in the associated Security Group, NACL and Route Table that would hinder the connection to TCP port 25 from this instance.

It hence seems that the issue is related to the instance's internal configuration. You could troubleshoot the instance on the OS level, for example you could check if you can connect to another mail server on port 25. In that case the issue could be related to the specific mail server that you are trying to reach. It would also be advisable to perform a packet capture and analysis on the instance (e.g. using tcpdump) to see what exactly is happening during the communication attempt.

Also you could launch a new clean Ubuntu instance into the same VPC and test the connectivity to an outside port 25 from it. If this works, then you could cross-examine settings on the working instance with the one of the instance that is having issues and then correct the configuration.

Lastly, you could also post more specific details (e.g. the exact error that you are getting etc.) on this Forum thread so that we can try to assist you further.

Regards,
awstomas

AWS
已回答 5 年前
1

I too am having this issue. It started about 3 weeks ago. I submitted a request for the block to be lifted but still haven't heard back yet. We are using a file share site that sends emails to recipients upon upload. I don't know who else I can contact though because there's no ticket created when submitting the remove port 25 throttle. Kind of frustrating that there's no clear path to resolution or followup.

Edited by: dieselxindustry on Feb 17, 2020 9:13 AM

已回答 4 年前
1

We just setup the production environment and went live few weeks ago everything seems to work fine but the Port 25 was somehow getting a timeout. After struggling for hours and troubleshooting firewalls and routing we found out that this is the restriction from AWS. We did submit a case to lift the restriction but still no response from the team also no place to track the request.

Can anyone from support team help here since it's our production env and we need to sort it out ASAP?

Tayyab
已回答 4 年前
0

Hello dieselxindustry,

I have checked internally your account and I can see that you have requested an SES sending increase limit on February 18th. Please note that the customer support team updated the case on February 19th with the approval.

If you would like to remove the restriction on port 25 from your EC2 instance, please follow the link below in order to complete the required form and we will be able to help you.
https://aws.amazon.com/premiumsupport/knowledge-center/ec2-port-25-throttle/

Thank you,
VasosAWS

已回答 4 年前
0

I have just become aware of the fact that port 25 was blocked on my EC2 instance at some point in early February this year.
We were able to send email without any problem until then.
But for some reason, and without any notice, someone decided to block port 25 for our machine, which resulted in many, many emails not reaching their destination and we never knew about it until someone pointed out that they were not receiving any reply from us!!!

This incompetence have cost us tremendously. Blocking port 25 is something you must inform with anticipation, instead of doing it without any notice whatsoever.

Hrich
已回答 4 年前
0

Duplicate message deleted - the first received a 500 error so I thought it didn't get posted.

Edited by: ErikFugletaint on Sep 26, 2021 8:16 AM

已回答 3 年前
0

Hi, Just had a similar issue, first it was

Because this request involves an account that meets one or more of the following criteria:
* Account has been previously implicated in the sending of unwanted mail (spam)
* Request is for a newly created account

then on querying what that mean (as had just set the account up, very first aws account ever...)

This account, or those linked to it, have been identified as having at least one of the following:
* A history of violations of the AWS Acceptable Use Policy
* A history of being not consistently in good standing with billing
* Not provided a valid/clear use case to warrant sending mail from EC2

Did you ever manage to solve it, seems pretty rude and unhelpful responses from aws?

richud
已回答 3 年前
0

I'm also facing this issue, they did it without informing us, which cost us dearly. They want to force the Simple Email Service on everyone out there who is using their services. Such an arrogant attitude.

Firoz
已回答 10 個月前

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