| Summary: | virt-manager generates ifcfg-br0 with the wrong value STP=on which causes restart of switches | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | iliya.chalamov |
| Component: | virt-manager | Assignee: | Cole Robinson <crobinso> |
| Status: | CLOSED INSUFFICIENT_DATA | QA Contact: | Virtualization Bugs <virt-bugs> |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | 6.3 | CC: | berrange, dyuan, laine, mzhan, rwu |
| Target Milestone: | rc | ||
| Target Release: | --- | ||
| Hardware: | x86_64 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2011-09-27 15:13:01 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
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Description
iliya.chalamov
2011-05-25 10:13:18 UTC
Hmm, libvirt defaults to stp=on for it's virtual network bridges, and man brctl strongly recommends always enabling stp. I can't say I know much about the motivation but I was taking the safe default. The UI does give the option of changing the value (though if the default is dangerous we should indeed change it). Dan or Laine, any comment on this? I'd like a clarification of what is meant by 'causes restart of switches' ? It is expected that when you have STP=on, that there will be a period of time in which network traffic is blocked on that NIC, while the switch does the spanning tree algorithm to detect network loops. This delay can be controlled via the forward delay settin. STP=on is intended to prevent accidental network loops. If a host has two network cards each in a bridge, and a guest is connected to both bridges, then the guest could potentially cause a network loop in the physical LAN. By choosing to have STP=on, we thus protect against a potential guest initiated denial of service attack. No response for a few months, closing as INSUFFICIENT_DATA. If this bug is still relevant, please reopen, providing the info requested in Comment #2 and Comment #3 |