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Accepted
Jason Swett
Asked: 2010-10-19 11:59:37 +0800 CST

Switching local DNS servers disrupts printer

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I have two DNS servers in my office, Gob and Tobias. They are both running Ubuntu and BIND. Their BIND config files are identical. We've been using Gob for the last month or so. When we switched to Tobias for the first time today, everything kept working fine except we were no longer able to print. Switching back to Gob fixed the problem.

Any idea as to why changing DNS servers, which doesn't seem to me to have all that much to do with printing, could make it so people can't print anymore?

Edit: After some more testing, it's unclear whether only Gob works, only Tobias works, it works sometimes under either, or if the printing problem is even related to the DNS server switch at all. Pretty cool.

domain-name-system networking printing bind

5 Answers

  1. A couple of things:

    1. Are clients configured to use Tobias as well as GOB for DNS name resolution?

    2. What is the TTL on the DNS record for the printer and did you wait for the TTL to expire or flush the DNS cache on the client before trying to print?

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  2. When you switched to using Tobias did you check on the print server that the printer can resolve?

    You don't happen to have everything DHCP do you? Often servers are set static. Check you've actually changed all DNS to point to Tobias.

    Restart all the LAN machines so their DHCP leases are renewed.

    Or do a

    ipconfig /release ipconfig /renew

    on the windows cmd line.

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  3. You didn't tell very much about the printers. There at least 2 possibilities here:

    1. People (their computers) not seeing the printers because they don't resolve anymore. Unlikely, because you said the DNS server where identical.

    2. Some printers require a DNS server to work (why ever, I#ve seen this with some HP and I also believe with some Canon printers. If the printers had only one server configured, and you took it offline, then someone has to tell the printers where the new DNS server is.

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  4. My first guess would be the configuration actually isn't identical, for whatever reason. Tobias is probably not resolving the printer, for whatever reason, and so clients can no longer find it. You can very easily check this:

    C:> nslookup <hostname of printer>  <ip of gob>
C:> nslookup <hostname of printer>  <ip of tobias>

    If they don't return the same thing, well, take a REALLY good look at the zone files, and check for /etc/hosts entries.

    The "sometimes" symptoms also make me think this is an issue, since it could be caused by cached DNS records, some clients using the IP rather than hostname, and/or some clients still using Gob as their nameserver.

    If both lookups return the same thing, it's likely a problem with the printer itself. Check network configs on the printer, as maybe it is dependent on DNS as others have suggested.

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  5. Best Answer

    The problem has gone away by itself, meaning all these answers are probably irrelevant. Sorry about that.

    Since Stack Overflow's interface forces me to keep my "accept rate" up or else people will whine about it, I'm putting this "answer" here so I can select it in a couple days.

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