Hostname for some clients show up in lowercase

[stonerl]

I'm using Pi-hole's DHCP server and have configured a static IP for some of the clients:

XX:XX:XX:XX:XX:84,192.168.42.20,Tonis-MBP
XX:XX:XX:XX:XX:E2,192.168.42.21,Tonis-iPhone
XX:XX:XX:XX:XX:35,192.168.42.22,Tonis-iPad
XX:XX:XX:XX:XX:91,192.168.42.23,Tonis-Apple-TV

In the top permitted/blocked client list and the query logs, some of the hostnames show up in lowercase:

tonis-mbp.internal
tonis-ipad.internal
tonis-iphone.internal

While others have the hostname that I set in the static config:

Tonis-Apple-TV.internal

On my Fritzbox, they all show up with the "correct" name:

Tonis-Apple-TV
Tonis-MBP
Tonis-iPad
Tonis-iPhone

Why is that?

[korhant]

Domain Name System (DNS) names are "case insensitive". This document
explains exactly what that means and provides a clear specification
of the rules https://datatracker.ietf.org/doc/html/rfc4343

[stonerl]

I know that they are case-insensitive. But that does not explain why only these 3 show up in lowercase and all the others in mixed case.

[DL6ER]

Do you, by any chance, have some screenshots for us? I went through the code (rather quickly TBH) and didn't see any places where we do a conversion to lower-case for client hostnames. But, yes, we definitely do this for domains so depending on if you see the hostname as a client descriptor or as a requested domain, differences in capitalization are actually expected.
Once we have more information, we can go and take a closer look again.

[stonerl]

Are these enough.

[secure-x7Es5gf]

Any updates on this? I'm having the same issue after upgrading to V6 and find it very annoying. Being able to see the case the way I enter it makes it much more readable and used to work fine in V5.

E.g: Bobs-MBP vs bobs-mbp, LivingRoomATV vs livingroomatv

[secure-x7Es5gf]

Still no updates?

[bcutter]

I noticed the exaxt same thing.

My investigation:

• All hostnames coming from my router as upstream DNS server for local hostnames are correctly shown as CaseSensitiveHostName.fritz.box for example
• All hostnames defined in https://pi.hole/admin/settings/dnsrecords are presented as casesensitivehostname.fritz.box

That's true for

• the Pi-Hole webinterface
• using nslookup, see below (run directly on Pi-Hole server):

nslookup xxx.xxx.x.xx pi.hole
x.x.xxx.x.in-addr.arpa	name = casesensitivehostname.fritz.box.

nslookup xxx.xxx.x.xx fritz.box
x.x.xxx.xxx.in-addr.arpa	name = CaseSensitiveHostName.fritz.box.

And that even according to the settings the hostname is stored with upper case in the pihole.toml:

sudo cat /etc/pihole/pihole.toml | grep xxx.xxx.x.x
    "xxx.xxx.x.x CaseSensitiveHostName.fritz.box",

Summary:

• Pi-Hole is the root cause
• Pi-Hole seems to be "compliant" according to previous information in this topic - but at the end it is still confusing
• I would prefer Pi-Hole would report hostnames exactly as defined. Not in plain lowercase only.

One GitHub issue on this timed out in May 2025:

Host names are not case-sensitive anymore

[nero355]

@bcutter

I would prefer Pi-Hole would report hostnames exactly as defined. Not in plain lowercase only.

But…
.
.
.
That’s not how the DNS protocol works ?!?!

Have you ever typed in any url in your browser with both upper and lower case letters ?!
I am guessing you have not and you will never need to either…