Bug 1691993 - Frequent IPv4 address changes result in constant SSH loss [NEEDINFO]
Summary: Frequent IPv4 address changes result in constant SSH loss
Keywords:
Status: NEW
Alias: None
Product: Fedora
Classification: Fedora
Component: NetworkManager
Version: 29
Hardware: armv7hl
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Lubomir Rintel
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks: ARMTracker
TreeView+ depends on / blocked
 
Reported: 2019-03-23 03:53 UTC by Jeffrey Walton
Modified: 2019-03-23 14:45 UTC (History)
12 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed:
bgalvani: needinfo? (noloader)


Attachments (Terms of Use)
DHCP server lease history (49.76 KB, image/png)
2019-03-23 03:53 UTC, Jeffrey Walton
no flags Details

Description Jeffrey Walton 2019-03-23 03:53:22 UTC
Created attachment 1547189 [details]
DHCP server lease history

This is kind of a shitty report. My apologies for that.

I have a Raspberry Pi 3B+ running Fedora 29, fully patched. Every half hour the RPI3 acquires a new IP address. This causes my SSH session to freeze. Once I get the "connection dropped" message I can use the new IP address and SSH back into the device. Ad infinitum.

I can duplicated the problem with both the armv7hl and aarch64 minimal images. The issue only occurs when using Fedora's images. I use Minimal images because the board is headless. I don't know if the issue affects GNOME or XFCE based images. I have a lot of IoT gadgets, and they use different OSes. Other OSes don't witness the problem.

The report is filled against Network Manager, but I suspect it is a confluence of components and events. The info below tries to describe the components and events.

==========

I have an internal DHCP server that only provides 172.16.*.* IPv4 leases. The server is IPFire firewall. DHCP leases expire in one hour to promote aggressive scavenging of leases.

There is also a Verizon gateway [upstream] in the network. The Verizon gateway also has a DHCP server that only provides 192.168.1.* IPv4 leases. Verizon traffic is blocked on the internal network.

Verizon gateway also has a Wireless access point. I don't use wireless on these devices. All of the devices are tethered using ethernet. All of the devices lack the password to join the network. (I don't even bother configuring or fixing wifi problems since ethernet is available).

The Fedora machine seems to be OK if I leave the hostname as "localhost". This morning I was connected over SSH for about 10 hours when the machine was named localhost. When I renamed the machine "rpi3b" the problem surfaced again. The IP address changed 3 times in the last 2 hours.

The typical sequence of SSH sessions using a non-localhost name are:

    ssh 172.16.4.170  # or whatever the starting IP address is
    <work 30 minutes, session killed>
    ssh 172.16.4.171  # incremented by 1
    <work 30 minutes, session killed>
    ssh 172.16.4.172  # incremented by 1
    <work 30 minutes, session killed>
    ssh 172.16.4.173  # incremented by 1
    <work 30 minutes, session killed>
    ...

When the problem occurs my DHCP server does not show a MAC address during DHCP registration. This is unusual; see attached image.

The issue was raised on the Fedora ARM mailing list but I have not been able to resolve it. Also see "Raspberry Pi 3B+ with Aarch64 image changing IP every half hour", https://lists.fedoraproject.org/archives/list/arm@lists.fedoraproject.org/thread/TWBVTKQP524KZ5DEZDJRJZD33T2JWNM3/ .

Stuart D. Gathman suggested this may be an IPv6 privacy option and cited https://blog.linitx.com/control-privacy-addressing-ipv6-linux/, but disabling IPv6 did not help. IPv6 is not configured, and it is not clear to me how IPv6 is affecting IPv4.

Comment 1 Beniamino Galvani 2019-03-23 14:45:38 UTC
Can you please set level=DEBUG in the [logging] section of /etc/NetworkManager/NetworkManager.conf, restart the NM service with "systemctl restart NetworkManager", reproduce the issue and then attach the output of "journalctl -u NetworkManager -b" ?


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