DNS Server lost after NAC Upgrade to 6.1.X

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  • Updated 3 years ago
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After I upgraded a few NAC Appliances from 5.X to 6.1.X or from 6.1.X to latest 6.1.182 I had sometimes the problem that NAC lost its DNS Server information in the /etc/resolvresolv.conf.

After dnetconfig (without changing something) all worked fine again.

Does anybody know a reason for that? It doen't happen on every appliance.

Best Regards
Michael
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Michael Kirchner

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Posted 4 years ago

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Rainer Adam

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No, I did not have any problems with it. I upgraded 6 NAC Gatways at one customer from 6.0 to 6.1 and it works fine. Last week I updated from 4.3 to 6.1 with 2 NAC GW's and it works also fine.
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James A, Embassador

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I see this sometimes on my NAC servers with two NICs. It happens because /etc/network/interfaces has gateway lines for each interface, which causes a hang while the network is being configured, and so the DNS configuration is never set in /etc/resolv.conf. My guess is sometimes dnetconfig has a race condition with this which is why it only works sometimes. I've been meaning to file a bug on this but haven't got around to it.
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James A, Embassador

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OK, so we have the same setup. Ubuntu ifupdown doesn't like it if two interfaces have a gateway. dnetconfig (and well /etc/init.d/staticroutes) does something different that does work, by using Linux routing tables from the look of it. This makes ifupdown not complete on boot, so DNS (which it configures) isn't configured either.
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Michael Kirchner

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Ok, great investigation! But I still don't get (sorry!) what you mean with "I got around to filing 01124098 on this"
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Drew C., Community Manager

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I believe he's referring to the GTAC case he has opened :)
(Edited)
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James A, Embassador

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Drew, that's exactly it. Would have replied earlier but I couldn't get the Extreme login to the community to work on my mobile.