SHIFT-WIKI - Sjoerd Hooft's InFormation Technology
This WIKI is my personal documentation blog. Please enjoy it and feel free to reach out through blue sky if you have a question, remark, improvement or observation. See below for the latest additions, or use the search or tags to browse for content.
Fix: ASDM: Fail to establish SSH session
Summary: A Fix for a Cisco ASA firewall when you can't login over SSH.
Date: Around 2007
Refactor: 16 January 2025: Checked links and formatting.
Symptom: Unable to establish a SSH session with a Cisco ASA firewall. After logging in using ASDM you see this error in the log:
fail to establish SSH session because RSA host key retrieval failed
To fix, go to the command line interface:
ASDM → Tools → Command Line Interface
And enter these commands:
conf t crypto key generate rsa general-keys modulus 1024
Now you can establish a connection over SSH.
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Fix: Red Hat GSSAPI Error
Summary: A fix for Red Hat server with login problems and GSSAPI errors in the /var/log/messages
Date: Around 2014
Refactor: 16 January 2025: Checked links and formatting.
If you experience the following errors in the /var/log/messages logfile:
sssd_be: GSSAPI Error: Unspecified GSS failure. Minor code may provide more information (Server not found in Kerberos database) sssd_be: GSSAPI Error: An invalid name was supplied (Success)
As well as long login times and failed login times, and after a successful logon the following message:
cannot find name for group ID XXXXX
Disable this line (if present) in the /etc/sssd/sssd.conf:
ldap_disable_referrals = true
and put this line in the config file:
ldap_referrals = false
Fix: Postfix: Database Older Than Source File
Summary: Fix the error 'Database Older Than Source File' in postfix on linux servers.
Date: Around 2014
Refactor: 6 January 2025: Checked links and formatting.
Fix: NTLDR missing
Summary: A fix for the Windows XP Boot error 'NTLDR missing'
Date: Around 2009
Refactor: 16 January 2025: Checked links and formatting.
Sometimes it happens, when you bootup Windows all you see is a black screen saying “NTLDR missing”. There are a lot of things that can cause this, but what I had last week was a new one for me, a virus had done this to one of my users. Note that in case you've had a virus on a system, even if you fixed it, you should consider reinstalling the system. Once a virus was active on a computer it should never be trusted again.