Bug 58237 - revise hostname limit of 13 characters
Summary: revise hostname limit of 13 characters
Status: CLOSED FIXED
Alias: None
Product: UCS@school
Classification: Unclassified
Component: Ucsschool-lib
Version: UCS@school 5.2
Hardware: Other Linux
: P5 normal
Target Milestone: UCS@school 5.2 v2-errata
Assignee: Jürn Brodersen
QA Contact: Arvid Requate
URL:
Keywords:
Depends on: 35599 40212 56128
Blocks:
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Reported: 2025-04-28 15:46 CEST by Jürn Brodersen
Modified: 2025-05-27 11:21 CEST (History)
9 users (show)

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What kind of report is it?: Bug Report
What type of bug is this?: 6: Setup Problem: Issue for the setup process
Who will be affected by this bug?: 3: Will affect average number of installed domains
How will those affected feel about the bug?: 3: A User would likely not purchase the product
User Pain: 0.309
Enterprise Customer affected?:
School Customer affected?: Yes
ISV affected?:
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Description Jürn Brodersen univentionstaff 2025-04-28 15:46:42 CEST
+++ This bug was initially created as a clone of Bug #56128 +++

10 years ago Bug 31688 claimed that the NETBIOS Name limit ist 13 characters in UCS. 
There is not any proof to be found that this statement is still or was ever valid. 

Bug 30255 states "the maximum length of a valid DC name is limited by Samba4" and "A valid NetBIOS name can not be longer than 13 characters" but links lateron https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2003/cc756101(v=ws.10)?redirectedfrom=MSDN#BKMK_NameLimits which clearly says 
"NetBIOS computer and domain names are limited to 15 characters"

https://wiki.samba.org/index.php/Active_Directory_Naming_FAQ#NetBIOS_Names says
"Whatever you use for your NetBIOS name, ensure it is just one word, no longer than 15 characters..."

Bug 40611 described a failed setup due to the length of the hostname but the join.log also says
"Our netbios name can be at most 15 chars long,..."
As a result Bug 42816 introduced a length limit of 14(!) characters for Docker-based hosts. 

-> This is inconsistent, hardly explainable and sometime annoying (see Bug 51901)

There may have been some scenarios in the past for example in UCS@School where hosts (administrative servers) have been autocreated by adding characters but this is not the case anymore. 



-> The limit sh
Comment 1 Arvid Requate univentionstaff 2025-05-14 14:15:45 CEST
Verified:
* Code review
* Advisories
Comment 2 Johannes Königer univentionstaff 2025-05-27 11:21:59 CEST
Errata updates for UCS@school 5.2 v2 have been released.

https://docs.software-univention.de/ucsschool-changelog/5.2v2/en/changelog.html
https://docs.software-univention.de/ucsschool-changelog/5.2v2/de/changelog.html

If this error occurs again, please clone this bug.