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Level 2: Rookie

Why is ip address for Moblie broadband range being blacklisted all the time?

Please see below:

 

Remote Server returned '550 5.7.501 Service unavailable, Client host blocked using Spamhaus. To request removal from this list see http://www.spamhaus.org/lookup.lasso (AS16042849)'

 

I have added a rule in the backend of exchange online to remove ip address from header. still bouncing.

 

Why is the telstra MBB ip range on a blacklist?

 

From Spamhaus:

 

Outbound Email Policy of The Spamhaus Project for this IP range:

This IP address range has been identified by Spamhaus as not meeting our policy for IP addresses permitted to deliver unauthenticated 'direct-to-mx' email to PBL users.

Important: If you are using any normal email software (such as Outlook, Entourage, Thunderbird, Apple Mail, etc.) and you are being blocked by this Spamhaus PBL listing when you try to send email, the reason is simply that you need to turn on "SMTP Authentication" in your email program settings. For help with SMTP Authentication or ways to quickly fix this problem click here.

 

Please note that it is running Outlook connected back to exchange online and using a TMBB device to connect.

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8 REPLIES 8
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Level 23: Superhero

Re: Why is ip address for Moblie broadband range being blacklisted all the time?

Sadly most mobile broadband services sit behind a carrier-grade NAT system, with many services sharing a single public IP address.

This means if one person does the wrong thing and gets the IP listed it can impact a wide group of customers.
If you've found a solution then don't forget to mark that post accordingly.
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Please note: I am not a Telstra employee and any posts or opinions are entirely my own and don't reflect any official company position.
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Level 2: Rookie

Re: Why is ip address for Moblie broadband range being blacklisted all the time?

That doesnt help all the remote users out there at all......especially using Mobile Broadband devices Smiley Sad

 

As far as I know you cant get a static ip for a MBD or can you now?

 

I really need to get this sorted...........and the worst part about it is it is not a single ip address but the entire range Smiley Sad

 

Does anyone have a solution or a workaround to this? i have tried restarting the mobile device and tried using a different method of connecting (iPhone Hotspot) but this is also getting bounce messages.

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Level 23: Superhero

Re: Why is ip address for Moblie broadband range being blacklisted all the time?

You can still get an singular public IP address assigned, but only on request, and only on business services.

 

This is the info Telstra has on the issue:
https://crowdsupport.telstra.com.au/t5/Broadband-nbn/Why-is-my-email-being-blacklisted/ta-p/76234

If you've found a solution then don't forget to mark that post accordingly.
If you think I've been of assistance to you please remember to let me know by clicking on the LIKE button.

Please note: I am not a Telstra employee and any posts or opinions are entirely my own and don't reflect any official company position.
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Level 2: Rookie

Re: Why is ip address for Moblie broadband range being blacklisted all the time?

That is a good guide but it still doesnt answer the bounce and range being blacklisted. I have spent hours on the phone with MS to get a workaround in place and it is very intermittent with bounces still being recieved.

 

I am trying to give my clients the best possible service with O365 but it is the range that is being blacklisted. We have checked the domain and everything and the only thing left is the IP range which as customers we have no control over.

 

The laptop is clean of viruses and trojans and malware.

 

This is getting very frustrating.

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Telstra Products & Services Team
Telstra Products & Services Team

Re: Why is ip address for Moblie broadband range being blacklisted all the time?


@MITSupport wrote:

That is a good guide but it still doesnt answer the bounce and range being blacklisted. I have spent hours on the phone with MS to get a workaround in place and it is very intermittent with bounces still being recieved.

 

I am trying to give my clients the best possible service with O365 but it is the range that is being blacklisted. We have checked the domain and everything and the only thing left is the IP range which as customers we have no control over.

 

The laptop is clean of viruses and trojans and malware.

 

This is getting very frustrating.


Telstra don't actively request blacklist removals from our customer IP ranges.

As mentioned, Telstra use CGNAT for our mobile base. This means you, and many other people will be sharing the same IP address at any point in time.

Sadly there is ALOT of compromised devices out there so the mobile range is often listed on Spamhaus and other spam lists.

You may request a delisting of the address, however as you are using NAT, the IP you have right now will most likely be different in an hour, 30mins or even less time unless you maintain a constant open connection.

This is probably why you are seeing intermittent results. You bounce around the available IP pool. Some are listed, some arn't.

 

Sadly there isnt much Telstra can do for you in this. As mentioned, the best fix is getting a static IP. You can delist it once, and assuming the devices sitting behind that mobile connection are no infected, then it should remain clean and working.

Most of these spam lists will only list an IP for a period of time. If bad traffic is not seen in say 48hours, the listing is removed. It varies from provider to provider.

 

This doesn't just affect mobile broadband (CGNAT) connections either. General broadband dyanmic IP's have the same problem. But the difference here is that you maintain the same IP for long periods of time, so its much easier to request a delist and then you won't have issues until you change IP's (maybe - if the new IP is listed).

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Telstra Products & Services Team
Telstra Products & Services Team

Re: Why is ip address for Moblie broadband range being blacklisted all the time?

To further my response above, there may be a solution for you, but I am not 100% sure on what you are trying to achieve nor the configuration.

 

Are you saying you are running your own in (client) house Microsoft Exchange server?

And when you send an email out (in the example of your first post) to an Outlook.com address, you mail was rejected for being on one of the Spamhaus lists.

 

If this describes the situation, then that is quite normal, and the issues you are seeing occur on all ISPs.

You can get around this though by relaying your outbound mail through the Telstra mail severs.

Outlook.com then sees your mail as coming from Telstra, and it won't be rejected.

You simply setup Exchange to relay all mail through mail.bigpond.com.

 

I can't assist with configuration of Exchange to do this, but I am sure Google will have an answer.

Please also note that this will only work while your client remains on a Telstra internet service. If the client has a failover internet connection to another provider, then the relay configuration would be broken and their outbound mail services would stop. If your client changes to another provider, they will need to reconfigure their relay settings to relay through their new provider.

 

If I have assumed the situation wrongly, then please explain your setup in a bit more detail.

 

Thanks.

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Level 2: Rookie

Re: Why is ip address for Moblie broadband range being blacklisted all the time?

Thanks for the reply Smiley Happy

 

Ok so the setup is this:

 

O365 Business Premium service - Hosted Exchange

 

All PC's running Outlook in cached Exchange mode - Connected directly to exchange online.

 

Mobile user 3 days per week where he is out onsite using a Telstra 4GX device. Will send sometimes and then bounces other times.

 

Works perfectly fine in the office but onsite not working. Domain setup is fine correct MX records in place.

 

Here is what Microsoft have said:

 

Regarding your additional question about the emails that are not being delivered while using a mobile hotspot connection, I analyzed the provided information and discussed this behavior with one of our Technical Leads and this is our feedback:

  • From the NDR message you provided it's clear that the IP used for sending the email is blacklisted by Spamhaus. This behavior is often encountered and is strictly related the your ISP, who's IP addresses were blacklisted due to spam reports.

Unfortunately due to security policies we cannot request Spamhaus to delist the IP range as you or the ISP should request this using the instruction link from the NDR message.

In conclusion, your current configuration is not having any mail-flow issues, as the behavior you are experiencing is caused by mobile internet service provider which has blacklisted IP addresses.

As we’ve managed to provide the information requested and fulfil the Scope of this Service Request, I’ll go ahead and archive this case.
Thank you very much for choosing Microsoft Online Services.
Best regards,

 

Now i have installed the Outlook app on the clients Samsung and also iPhone and they also receive bounce messages.

 

How do you get a static IP address for a Mobile broadband device? I am unsure if it is a pre paid or a post paid device. I am guessing that if it is a pre paid device - no static ip.

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Telstra Products & Services Team
Telstra Products & Services Team

Re: Why is ip address for Moblie broadband range being blacklisted all the time?

To be honest, this sounds a bit odd.

What I would suggest is this:

When the bounces start occuring, visit this website: https://www.whatismyip.com/

Note down the IP address it presents. It should be a 1.something IP address.

 

Now enter the IP into this page: https://www.spamhaus.org/lookup/

You should get three lines that might say

x is not listed in the SBL

x is not listed in the PBL

x is not listed in the XBL

 

 

I expect the IP is listed on PBL, unsure of the others.

It almost sounds like Microsoft is rejecting PBL listed IP's connecting to hosted exchange. Which would be really weird indeed. You normally don't reject outbound mail requests from a PBL listed address, precicessly because of what you are seeing right now.

 

But I suspect the easiest solution here is the static IP.

To request one you will need a few things:

- The account the mobile device is assigned to, with pre-arranged permission to talk on behalf of the account (security requirement on Telstra's side)

- The mobile number is always handy, if this is a mobile phone.

 

Speak with sales and request a static IP for your mobile service. Explain your reasoning, that you require it for Hosted Exchange access.

Alternatively, you can try the livechat page.

https://www.telstra.com.au/chatnow/landing

 

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