"Key has already been taken" when using SMTP-IP

[willpower232]

Discussed in https://github.com/orgs/postalserver/discussions/3309

^{Originally posted by SpookOz February 24, 2025}
Hi all. I would like to use the same IP address as credentials for multiple servers. However, if I try to do so, it only allows my to specify the IP for the 1st server. After that, if I try to use the same IP for other servers, I get the error "Key has already been taken". I assume it is using the IP as the key. Is there a way to get around this or have an IP as a universal credential?

Thanks in advance for any advice

[willpower232]

@SpookOz there will be a unique constraint either in the code or the database, I'm not sure where off the top of my head, are you able to investigate at all?

[SpookOz]

@willpower232 I'm no db admin, but I can run queries. Would you like me to search the tables for the IP address and see where / if it is showing up?

[SpookOz]

Not sure if this helps, but it is in the db in the tables "credentials" in the column "key":

SELECT * FROM credentials 
WHERE `key` LIKE '%8.8.8.8%';

(obviously replaced my IP with Google's ;))

[SpookOz]

So I'm thinking maybe the key needs to be generated randomly like is done with SMTP credentials rather than just using the IP address as the key maybe?

[willpower232]

Adding another column to the database would make the fix quite messy, I believe the code has already pivoted to uniquely identifying credentials by uuid anyway.

I think the answer is to modify the validation here but I don't know enough ruby

postal/app/models/credential.rb

Line 28 in fd3c7cc

validates :key, presence: true, uniqueness: { case_sensitive: false }

As an aside, a similar error happens in IP Pools but I don't know how related that is #1190 #610

[SpookOz]

Ah. I know exactly zero ruby :D. I might be over-simplifying, but the SMTP credentials option seems to generate a random key. would it be possible to just copy the code for that from to the SMTP-IP credential?

[willpower232]

well it needs to know the IP address so replacing it with the auto generated key would upset it?

[SpookOz]

Oh I assumed that key and the IP address were stored in different columns - like the SMTP credentials and the key are. Maybe they're not?

[iammattmartin]

This error also happens when trying to use the same IP on a domain that has already been deleted and the auth credentials have gone with it (they are not deleted in the db).