Recurring checksum problems when using DNF

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1

I am using a fresh installation of Fedora 42, on which, apart from a few basic tools, only Nvidia drivers (with sercure-boot support) were installed from RPMFusion. I’ll post more details about the version below.

During almost every session on the computer, when I use a DNF command, which forces to check the repositories (for example, dnf search), I get the following errors about incorrect checksums and 404 statuses for some mirrors:

...

>>> Downloading successful, but checksum doesn't match. Calculated: 98f903f88c9483cd64474dd2b1648a1e2
>>> Downloading successful, but checksum doesn't match. Calculated: 98f903f88c9483cd64474dd2b1648a1e2

...

>>> Status code: 404 for https://ftp.icm.edu.pl/pub/Linux/fedora/linux/updates/42/Everything/x86_64/r
>>> Status code: 404 for https://ftp.icm.edu.pl/pub/Linux/fedora/linux/updates/42/Everything/x86_64/r
>>> Status code: 404 for http://ftp.icm.edu.pl/pub/Linux/fedora/linux/updates/42/Everything/x86_64/re

...

I have set fastestmirror to False in the dnf.conf file, according to a suggestion on one of the forum threads. After executing the dnf clean command, the problem goes away within a session, but reappears on subsequent sessions. First time I noticed that problem was on 4th July 2025, and the last attmpet on which the problem still occured was on 9th July 2025.

  • Is it normal for this incidence to occur so frequently?
  • Should I be concerned about something from a security standpoint (supply-chain attack)?
  • Is it possible for me to verify whether the repositories (especially mirrors, which are hosted by third-party domains) used by my systems are safe?
  • Since the checksums don’t match, does my system/dnf know to not use a given mirror?

Thanks in advance for your help and best regards,
Krzysztof

System details:

Operating System: Fedora Linux 42 (Workstation Edition)
Kernel: Linux 6.15.4-200.fc42.x86_64
Architecture: x86-64
Hardware Model: Legion Slim 5 16AHP9

Output of dnf --version:

dnf5 version 5.2.13.1
dnf5 plugin API version 2.0
libdnf5 version 5.2.13.1
libdnf5 plugin API version 2.2

Loaded dnf5 plugins:
  name: builddep
  version: 1.0.0
  API version: 2.0

  name: changelog
  version: 1.0.0
  API version: 2.0

  name: config-manager
  version: 0.1.0
  API version: 2.0

  name: copr
  version: 0.1.0
  API version: 2.0

  name: needs_restarting
  version: 1.0.0
  API version: 2.0

  name: repoclosure
  version: 1.0.0
  API version: 2.0

  name: reposync
  version: 1.0.0
  API version: 2.0

Output of dnf repo list --all (in order to show what repositories are used):

repo id                                        repo name                                             status
code                                           Visual Studio Code                                   enabled
copr:copr.fedorainfracloud.org:phracek:PyCharm Copr repo for PyCharm owned by phracek              disabled
fedora                                         Fedora 42 - x86_64                                   enabled
fedora-cisco-openh264                          Fedora 42 openh264 (From Cisco) - x86_64             enabled
fedora-cisco-openh264-debuginfo                Fedora 42 openh264 (From Cisco) - x86_64 - Debug    disabled
fedora-cisco-openh264-source                   Fedora 42 openh264 (From Cisco) - x86_64 - Source   disabled
fedora-debuginfo                               Fedora 42 - x86_64 - Debug                          disabled
fedora-source                                  Fedora 42 - Source                                  disabled
google-chrome                                  google-chrome                                       disabled
rpmfusion-nonfree-nvidia-driver                RPM Fusion for Fedora 42 - Nonfree - NVIDIA Drive    enabled
rpmfusion-nonfree-nvidia-driver-debuginfo      RPM Fusion for Fedora 42 - Nonfree - NVIDIA Drive   disabled
rpmfusion-nonfree-nvidia-driver-source         RPM Fusion for Fedora 42 - Nonfree - NVIDIA Drive   disabled
rpmfusion-nonfree-steam                        RPM Fusion for Fedora 42 - Nonfree - Steam           enabled
rpmfusion-nonfree-steam-debuginfo              RPM Fusion for Fedora 42 - Nonfree - Steam Debug    disabled
rpmfusion-nonfree-steam-source                 RPM Fusion for Fedora 42 - Nonfree - Steam Source   disabled
updates                                        Fedora 42 - x86_64 - Updates                         enabled
updates-debuginfo                              Fedora 42 - x86_64 - Updates - Debug                disabled
updates-source                                 Fedora 42 - Updates Source                          disabled
updates-testing                                Fedora 42 - x86_64 - Test Updates                   disabled
updates-testing-debuginfo                      Fedora 42 - x86_64 - Test Updates Debug             disabled
updates-testing-source                         Fedora 42 - Test Updates Source                     disabled
2

see also Dnf checksum and 404 errors - #2 by decathorpe

3

The command dnf repolist gives the results in a less verbose and more usable format since it only shows the enabled repos. The way you show it includes all installed repos (both enabled and disabled) so you need to view the first and last columns to identify the enabled repos.

The 404 errors show that the requested file was not available on the repo being queried
The checksum errors indicate that the downloaded file was not an exact match for the expected file from the source and the file will be downloaded again.

Checksum errors usually indicate some problem with the internet where a file was not properly downloaded and the checksum is to verify the file integrity. This happens from time to time and is a security check to prevent attempted installs from a damaged file. Unless it is happening 100% of the time on the same mirror I would not be concerned.

The 404 errors usually indicate that the mirror in question is not fully in sync with the master repo (either a timing issue or a server issue) and also are not really of concern. When a new update is pushed out it takes time for the mirrors to complete a sync and the area may also be a factor in delays.

I see the same thing today when attempting an update. Be patient and try your update later today or tomorrow