Chapter 8. Troubleshooting
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## Chapter 8. Troubleshooting

## Common Problems

### It's not working; how can I figure out what's wrong?

The best solution to solving installation and configuration issues is to take preventative measures by setting up logging files beforehand. The log files provide a source of hints and information that can be used to figure out what went wrong and how to fix the problem.

## Incrementing and Changing the Serial Number

Zone serial numbers are just numbers — they aren't date related. A lot of people set them to a number that represents a date, usually of the form YYYYMMDDRR. Occasionally they will make a mistake and set them to a "date in the future" then try to correct them by setting them to the "current date". This causes problems because serial numbers are used to indicate that a zone has been updated. If the serial number on the slave server is lower than the serial number on the master, the slave server will attempt to update its copy of the zone.

Setting the serial number to a lower number on the master server than the slave server means that the slave will not perform updates to its copy of the zone.

The solution to this is to add 2147483647 (2^31-1) to the number, reload the zone and make sure all slaves have updated to the new zone serial number, then reset the number to what you want it to be, and reload the zone again.

## Where Can I Get Help?

The Internet Systems Consortium (ISC) offers a wide range of support and service agreements for BIND and DHCP servers. Four levels of premium support are available and each level includes support for all ISC programs, significant discounts on products and training, and a recognized priority on bug fixes and non-funded feature requests. In addition, ISC offers a standard support agreement package which includes services ranging from bug fix announcements to remote support. It also includes training in BIND and DHCP.

To discuss arrangements for support, contact info@isc.org or visit the ISC web page at http://www.isc.org/services/support/ to read more.

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