> Source: [sk173934](https://support.checkpoint.com/results/sk/sk173934)

# sk173934 - How to create Domain Management Servers with a netmask different than that of the Multi-Domain Server

| Property | Value |
|----------|-------|
| Solution ID | sk173934 |
| Date Created | 2021-06-07 |
| Last Modified | 2022-12-05 |
| Technical Level | General |
| Products | Security Management Server |
| Versions | R81 (EOS) |

## Solution

This problem was fixed. The fix is included in:

* [Check Point R81.10](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk170416)
* [Jumbo Hotfix Accumulator for R81](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk170114) starting from Take 42
* [Jumbo Hotfix Accumulator for R80.40](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk165456) starting from Take 126
* [Jumbo Hotfix Accumulator for R80.30](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk153152) starting from Take 237

If you choose not to upgrade:
Create a file named `user_defined_netmask` in `$MDSDIR/conf` and write in it the netmask that is used for all Domain Management Servers on the Multi-Domain Server.  

1. Create the file from Expert mode:  
   # $MDSDIR/conf/user_defined_netmask
2. Enter the netmask in the following format, the example below is for a /24:  
   255.255.255.0
3. Verify the file was created correctly:   
   # cat /opt/CPmds-R81.10/conf/user_defined_netmask  
   255.255.255.0
4. Restart the Multi-Domain services:   
   # mdsstop;mdsstart
The updated network masks are visible in the output of the 'ifconfig' command from Expert mode.

---

# Agent Instructions

This content is from the Check Point Support Center (https://support.checkpoint.com), the official knowledge base for Check Point cybersecurity products.

## Navigating This Knowledge Base

- **Complete index**: [llms.txt](https://support.checkpoint.com/llms.txt)
- **All SK articles**: [SecureKnowledge Sitemap](https://support.checkpoint.com/sitemaps/secureknowledge-sitemap-index.xml)
- **SK article URL pattern**: `https://support.checkpoint.com/results/sk/{skId}`
- **Markdown responses**: AI bot User-Agents automatically receive `text/markdown` content