Moving to a new IP Address - What is the best way to handle this ?

Problem reported by Curtis Kropar www.HawaiianHope.org - 10/15/2025 at 1:41 PM

Submitted

This weekend we are moving our server to a new IP Address (we are physically moving our office 3 miles and there is no way to take our IP Address with us.)

I know we have to update the PTR record with the ISP. I will not know what the new IP address is till later today. Is there any way to include that IP address (today) in header traffic so it builds some type of reputation before we do a cold cut over move over the weekend ?

www.HawaiianHope.org - Providing technology services to non profit organizations, low income families, homeless shelters, clean and sober houses and prisoner reentry programs. Since 2015, We have refurbished over 11,000 Computers !

8 Replies

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Roger Replied

10/15/2025 at 2:19 PM

Well, I see several ways to avoid stress. Just set up NAT from the existing connection to the other location and forward the traffic there. Do the same in reverse.

Option two: work with rinetd and simply set up port forwarding to the new IP address for incoming connections. Outgoing connections would then use your existing address.

Douglas Foster Replied

10/16/2025 at 4:21 AM

This has been discussed before, and the optimal solution is to gradually shift traffic from old to new address. But that seems difficult to implement in any scenario and probably not feasible at all for your situation.

As long as you have DKIM signing for your domain, and a DMARC policy so that receivers jook for it, I would not expect problems.

As soon as you have the new address, add it to your SPF record and configure the SWIP/PTR address. On your A record, set TTL low enough so that the address will time out while the move is in process. On the night of the move, change the A record to the new address when you shut down to start the move.

I don't work for Microsoft or Google, so no guarantees, just opinions.

Curtis Kropar www.HawaiianHope.org Replied

10/16/2025 at 3:13 PM

"As soon as you have the new address, add it to your SPF record and configure the SWIP/PTR address."

I know what PTR is, what is SWIP ? Also, As this is a server move, most are pointed to our mail hosting domain. I have to go look for certain, but I might need to update all domains (SPF) on the server ?

Douglas Foster Replied

10/16/2025 at 7:40 PM

SWIP = Shared Who is for IP. Same as PTR but it emphasizes the fact that you do not own the reverse DNS domain that hosts your PTR record

It is the lingo that my ISP used when I was setting up my

If you host multiple domains, they all need an SPF update. An include might make it easier for future changes. I assume you will know the new IP address well before the move, so that can be added to SPF without removing the old one.

A record is trickier. My first edit suggested using two addresses on one name, but I removed that because it will not produce the desired result. Short TTL will work. Hopefully you only have only one MX host name for all domains?

Sabatino Replied

10/16/2025 at 11:31 PM

Hi Curtis.

Unfortunately, warming up the new IP won't be painless.

It's not just a matter of PTR, SPF, and reputation.

The big email providers (Microsoft first and foremost) will block it as soon as they see the new IP, even if it has a good reputation and is clearly associated with a domain they already know, after receiving significant traffic from the new IP (I have no idea what the limit is).

presumed culprit :-(

You'll have to open the usual ticket; they'll respond with an automated system, and you'll respond to that too. At that point, they'll unblock you. Unfortunately, it will take a few days. :-(

So, when the time comes, have a known IP ready to divert outgoing traffic to MS domains and anyone else who does the same.

Sabatino Traini Chief Information Officer Genial s.r.l. Martinsicuro - Italy

Douglas Foster Replied

10/17/2025 at 3:16 AM

Since we don't have the routing rules Sabatino has requested many times, I don't understand how the warm-up strategy is even possible. Additionally, it does not appear that Curtis will have new and old IP addresses available at the same time.

What can be done is to create accounts on the major players. Add some of your sending accounts to the contacts list of that account. Send test messages to those new accounts before the move, and again afterward. If the messages do not come through, you can open tickets as a recipient. That is more likely to get results than opening a ticket as a sender.

Zach Sylvester Replied

10/17/2025 at 8:05 AM

Employee Post

Hey Doug,

We’ve already got improvments to this area in progress.

Outbound mail Routing Rules and an enhanced IP Rotation system are planned to provide much greater delivery control. Administrators will have the ability to decide where specific messages get routed for delivery and more. This will certainly help with situations like these.

These features are coming soon and will bring a lot more flexibility to outbound delivery and routing management.

Kind Regards,

Zach Sylvester Software Developer SmarterTools Inc. www.smartertools.com

Sabatino Replied

10/21/2025 at 2:48 AM

I can't wait for this to happen.

I really miss routing rules.

Sabatino Traini Chief Information Officer Genial s.r.l. Martinsicuro - Italy

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