---
name: "gss"
section: "5"
platform: "macos"
package: "Heimdal"
version: "710.100.4"
release: "macOS 26.5"
platforms: ["macos"]
url: "https://new.carta.tech/gss/5"
---

# gss(5)

how to configure gss framework

## NAME

**gss** – how to configure gss framework

## DESCRIPTION

The **gss** GSS.frameworks have several configuration domains, all can configured with [defaults(1)](/defaults/1.md).

Configuration can be stored both in the user's configuration ( *~/Library/Preferences*) and system ( */Library/Preferences* *).*

## CONFIGURATION OPTIONS

Use gsstool(1) to list the supported options and their settings:

gsstool supported-mech --options

Common options are:

- NTLM 'Force NTLMv1'

  Force client to use NTLMv1

- NTLM NTLMv1

  Enable support for NTLMv1 in both client and server

- NTLM NTLMv2

  Enable support for NTLMv2 in both client and server

- NTLM 'NTLM session key'

  Require backends to support for NTLMv2 session key, Lion and earlier dont support this.  Session keys is required for NTLM MIC that stops reflection attacks.

- NTLM 'AllowedHosts'

  What hosts that NTLM is allowed to be used for. When there a host that is not on the list, NTLM will not be used. File globbing is used when matching and it's case insensitive.  When there is no configuration, all hosts are allowed.

  ```
  defaults write com.apple.GSS.NTLM AllowedHosts -array host.local '*.my.domain'
  ```

## NTLM options

If you want to disable NTLM support completely in both the acceptor (server) and initiator (client), you need disable both NTLMv1 and NTLMv2, and set their values to boolean false or 0.

```
defaults write com.apple.GSS.NTLM NTLMv1 -bool false
defaults write com.apple.GSS.NTLM NTLMv2 -bool false
```

## APPLE MAC OS X

You can use the defaults write command to change the options, for simple boolean options, use this:

defaults write com.apple.GSS.NTLM NTLMv1 -bool false

You can also turn on debugging (output in syslog) using:

defaults write com.apple.GSS DebugLevel -int 10

open -a Console

## SEE ALSO

[defaults(1)](/defaults/1.md), gss\_mo(3), heimdal\_debug(1)