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Description of problem: Network Manager deletes DNS when private network downed. Adam: I noticed one other thing. I have 2 interfaces. eth0 and eth1. eth0 configured with DNS1= and DNS2= for DNS servers. eth1 on a private network segment, so no DNS servers. iftup eth0, and everything looks good, DNS goes in resolv.conf ifup eth1, all still good. ifdown eth1 (so eth0 still up) and resolv.conf loses all nameservers. No sure if that's really NM, or if that's a problem with the ifup/ifdown stuff. me: that sounds like a good bug. I can just imagine that happening and I think I know why. Version-Release number of selected component (if applicable): How reproducible: 100% Steps to Reproduce: 1. eth0 public network with defined DNS, eth1 private network 2.ifup eth0 all ok 3.ifup eth1 all ok 4.ifdown eth1 resolve.conf emptied of contents Actual results: resolve.conf emptied of contents Expected results: resolve.conf only modified for lines related to ethernet device being toggled. Additional info:
Is NetworkManager allowed to control eth1 or has eth1 been excluded from NM via NM_CONTROLLED=no?
Any response for the question in comment 2?
The problem is that since eth0 isn't controlled by NM, there's no way to tell NM what's happening when eth0 is configured. That's the problem with a shared file like resolv.conf. If two things are touching it neither knows about the other. NM only knows about the details of things that you let it manage, so if eth0 isn't managed by NM, anything that happens with eth0 is obviously out of the control and awareness of NM. We can only realistically handle the case where (a) something is set up before NM starts and (b) NM never brings any devices up or down. But in the scenario where NM is allowed to manage some devices and not allowed to manage other devices, it has no idea about default routes or resolv.conf information of those other devices. (it's worse for DNS than routing because at least routes are tagged with an interface. DNS is global but there's no indication that a nameserver is only valid for one interface and not for another...) Is there any particular reason eth0 cannot be managed by NM? Is eth0 a bridge or vlan?
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This request was erroneously removed from consideration in Red Hat Enterprise Linux 6.4, which is currently under development. This request will be evaluated for inclusion in Red Hat Enterprise Linux 6.4.
What ifcfg files are there in /etc/sysconfig/network-scripts? Also, can you attach /var/log/messages when the problem occurs?