The following kernel error occurs when the MTU is specified under a subinterface rather than under the VLAN interface:

root@dell-s3000-04:~# ifreload -a -X eth0
warning: failed to execute cmd 'ip -force -batch - [addr add 1.1.4.1/24 dev swp52.100
link set dev swp52.100 mtu 9000 
]'(RTNETLINK answers: Numerical result out of range
Command failed -:2)

If you configure an interface so it can to obtain both IPv4 and IPv6 IP addresses via DHCP, ifupdown2 will honor only the first configuration and ignore the second.

In the following example configuration, ifupdown2 will only issue an IPv4 DHCP address for swp1, but not the IPv6 address.

auto swp1
iface swp1 inet dhcp
    link-speed 10000
    link-duplex full
    link-autoneg off

auto swp1
iface swp1 inet6 dhcp

The following SFF message appears every 5 seconds in syslog:

cumulus@switch:~$ tail -f /var/log/syslog 
2016-08-06T12:18:56.095606-04:00 cumulus portwd: invalid SFF identifier: 0x0c
2016-08-06T12:19:01.113397-04:00 cumulus portwd: invalid SFF identifier: 0x0c
2016-08-06T12:19:01.121068-04:00 cumulus portwd: invalid SFF identifier: 0x0c
2016-08-06T12:19:01.121698-04:00 cumulus portwd: invalid SFF identifier: 0x0c
2016-08-06T12:19:06.139373-04:00 cumulus portwd: invalid SFF identifier: 0x0c
2016-08-06T12:19:06.147045-04:00 cumulus portwd: invalid SFF identifier: 0x0c
2016-08-06T12:19:06.147677-04:00 cumulus portwd: invalid SFF identifier: 0x0c
2016-08-06T12:19:11.165355-04:00 cumulus portwd: invalid SFF identifier: 0x0c
2016-08-06T12:19:11.173134-04:00 cumulus portwd: invalid SFF identifier: 0x0c
2016-08-06T12:19:11.173747-04:00 cumulus portwd: invalid SFF identifier: 0x0c
2016-08-06T12:19:16.191418-04:00 cumulus portwd: invalid SFF identifier: 0x0c
2016-08-06T12:19:16.199154-04:00 cumulus portwd: invalid SFF identifier: 0x0c
2016-08-06T12:19:16.199805-04:00 cumulus portwd: invalid SFF identifier: 0x0c

When a traditional mode bridge is configured and the peerlink is tagged but the clagd bonds are native VLANs, clagd appears to try and sync the MAC addresses learned using the VLAN tag from the peerlink.

This causes the MAC address not to be synced correctly on the peer.

The mgmt-vrf package has a dhclient exit hook that incorrectly assumes that DHCP is used only with the management interface. If management VRF is enabled, it inserts default routes from the DHCP server into the management table.

Until this issue is resolved, do not use DHCP with the front panel (switch) ports. If you need DHCP for a switch port, disable Management VRF and assign the port to a VRF.

Cumulus Linux defaults to using PMTU to discover if a path has a lower MTU than what is set on its local interfaces. If an ICMP - Fragmentation Needed packet is received on an interface associated with a VRF, the MTU change for the remote address is not properly handled. The end result is that packets exceeding the MTU going through that network segment are dropped.

To work around this issue until it is resolved, do one of the following:

• Disable PMTU. This does not set the "don't fragment" bit in the IP header, allowing nodes to fragment the packet if needed.
  

  cumulus@switch:~$ sudo sysctl -w net.ipv4.ip_no_pmtu_disc=1

• Manually reduce the MTU on the interface. Add mtu <value> to the stanza for that interface in /etc/network/interfaces.

When broadcast video is sent over multicast with a number of senders running, the flooding approaches caused major issues, as the maximum available bandwidth was saturated on an individual port, and started dropping.

An issue occurrs where only counter samples are generated when hsflowd is configured correctly, but no sFlow sampled packets left the switch.

Manually calling portsamp and specifying an NFLOG group causes the ingress samples to leave the switch. You do this in /proc/bcm/knet/sample_groups:

cumulus@switch:~$ cat /proc/bcm/knet/sample_groups 
Sample NFLOG group (unit 0): 
rx=1
tx=0

A Linux kernel vulnerability was found that when the GNU Compiler Collection (gcc) stack protector is enabled, it uses an incorrect buffer size for certain timeout data, which allows local users to cause a denial of service (stack memory corruption and panic) by reading the /proc/keys file.

This issue is fixed in Cumulus Linux 3.2.0.

dnsmasq port 53 has been disabled by default on all platforms except Cumulus RMP, as enabling it creates a security vulnerability.

If your system uses dnsmasq, run the following command to enable it:

cumulus@switch:~$ sudo systemctl enable dnsmasq

If either of the following is configured:

net.ipv4.ip_forward == 0 

or:

net.ipv6.conf.all.forwarding == 0 

The hardware still forwards packets if there is a neighbor table entry pointing to the destination.

routes: 16384 <<<< if all routes are ipv4 
 long mask routes 256 <<<< i.e., routes with a mask longer 
       than the route mask limit 
 route mask limit 64
 host_routes: 8192 
 ecmp_nhs: 4044 
 ecmp_nhs_per_route: 52 

cumulus@switch:~$ sudo cl-resource-query
 hosts : 3 
 all routes : 29 
 IP4 routes : 17 
 IP6 routes : 12 
 nexthops : 3 
 ecmp_groups : 0
 ecmp_nexthops : 0
 mac entries : 0 / 131072 
 bpdu entries : 500 / 512

When ptmd is incorrectly in a failure state and the Zebra interface is enabled, PIF BGP sessions are not establishing the route, but the subinterface on top of it does establish routes.

If the subinterface is configured on the physical interface and the physical interface is incorrectly marked as being in a PTM FAIL state, routes on the physical interface are not processed in Quagga, but the subinterface is working.

Steps to reproduce:

cumulus@switch:$ sudo vtysh -c 'show int swp8' 
Interface swp8 is up, line protocol is up 
PTM status: fail
index 10 metric 1 mtu 1500 
 flags: <UP,BROADCAST,RUNNING,MULTICAST>
 HWaddr: 44:38:39:00:03:88 
 inet 12.0.0.225/30 broadcast 12.0.0.227 
 inet6 2001:cafe:0:38::1/64 
 inet6 fe80::4638:39ff:fe00:388/64 
cumulus@switch:$ ip addr show | grep swp8 
 10: swp8: <BROADCAST,MULTICAST,UP,LOWER_UP> 
  mtu 1500 qdisc pfifo_fast state UP qlen 500 
  inet 12.0.0.225/30 brd 12.0.0.227 scope global swp8 
 104: swp8.2049@swp8: <BROADCAST,MULTICAST,UP,LOWER_UP> 
  mtu 1500 qdisc noqueue state UP 
  inet 12.0.0.229/30 brd 12.0.0.231 scope global swp8.2049 
 105: swp8.2050@swp8: <BROADCAST,MULTICAST,UP,LOWER_UP> 
  mtu 1500 qdisc noqueue state UP 
  inet 12.0.0.233/30 brd 12.0.0.235 scope global swp8.2050 
 106: swp8.2051@swp8: <BROADCAST,MULTICAST,UP,LOWER_UP> 
  mtu 1500 qdisc noqueue state UP 
  inet 12.0.0.237/30 brd 12.0.0.239 scope global swp8.2051 
 107: swp8.2052@swp8: <BROADCAST,MULTICAST,UP,LOWER_UP> 
  mtu 1500 qdisc noqueue state UP 
  inet 12.0.0.241/30 brd 12.0.0.243 scope global swp8.2052 
 108: swp8.2053@swp8: <BROADCAST,MULTICAST,UP,LOWER_UP>
  mtu 1500 qdisc noqueue state UP 
  inet 12.0.0.245/30 brd 12.0.0.247 scope global swp8.2053 
 109: swp8.2054@swp8: <BROADCAST,MULTICAST,UP,LOWER_UP> 
  mtu 1500 qdisc noqueue state UP 
  inet 12.0.0.249/30 brd 12.0.0.251 scope global swp8.2054
 110: swp8.2055@swp8: <BROADCAST,MULTICAST,UP,LOWER_UP>
  mtu 1500 qdisc noqueue state UP 
  inet 12.0.0.253/30 brd 12.0.0.255 scope global swp8.2055
cumulus@switch:$ bgp sessions: 
 12.0.0.226 ,4 ,64057 , 958 , 1036 , 0 , 0 , 0 ,15:55:42, 0, 10472 
 12.0.0.230 ,4 ,64058 , 958 , 1016 , 0 , 0 , 0 ,15:55:46, 187, 10285
 12.0.0.234 ,4 ,64059 , 958 , 1049 , 0 , 0 , 0 ,15:55:40, 187, 10285 
 12.0.0.238 ,4 ,64060 , 958 , 1039 , 0 , 0 , 0 ,15:55:45, 187, 10285 
 12.0.0.242 ,4 ,64061 , 958 , 1014 , 0 , 0 , 0 ,15:55:46, 187, 10285 
 12.0.0.246 ,4 ,64062 , 958 , 1016 , 0 , 0 , 0 ,15:55:46, 187, 10285 
 12.0.0.250 ,4 ,64063 , 958 , 1029 , 0 , 0 , 0 ,15:55:43, 187, 10285 
 12.0.0.254 ,4 ,64064 , 958 , 1036 , 0 , 0 , 0 ,15:55:44, 187, 10285 

Cumulus VX triggers a route-map update before the user finishes editing the route map, resulting in an incorrect route map being used. The route-map update trigger should only occur when user finishes editing the map.

Cumulus Networks is working to fix this issue.

To work around this issue, remove any old redistribute command configurations before adding a new one with or without route-map as a parameter.

For example, if OSPF has a redistribute configuration such as redistribute bgp route-map redist-map-name, you would enable redistribution without a route-map by following these steps in OSPF configuration mode:

1. no redistribute bgp
2. redistribute bgp

You would perform a similar sequence of commands for redistribution changes in BGP as well.

The LNV packages are not installed when you upgrade Cumulus VX. You can get the latest version of LNV for this release of Cumulus VX by installing the LNV packages for the registration and service node daemons using apt-get install vxfld-vxrd and/or apt-get install vxfld-vxsnd, depending upon how you intend to use LNV.

While OSPF area ID configuration in Quagga allows for the value to be specified in either dotted decimal format, or as an integer, values specified as an integer will be converted into dotted decimal format when displayed, causing potential confusion for the operator.

This issue does not impact OSPF functionality; only the display output. However, it is recommended that the OSPF area ID is specified in dotted decimal format for consistency.

When a link is admin down and carrier is on, the IPv4 nexthop entry is marked dead, but the IPv6 nexthop entry is deleted, and will not be restored when the link is admin up. However, if carrier is off, the IPv6 nexthop is marked dead and not deleted. This inconsistency in admin down behavior is being investigated.

In a VRR configuration, any interface-specific routing configuration (e.g., OSPF mode of operation) specified on the subinterface having a virtual IP address does not take effect. This is because when an operator has specified a virtual IP on a bridge, the system creates another internal interface bridge with the virtual IP and MAC. These two interfaces are treated distinctly by Quagga, so any interface-specific routing configuration on the bridge does not get carried over to the second bridge.

In a VRR deployment needing any interface-specific routing configuration on the interface with a virtual IP address, the routing configuration has to be specified against the internally-created virtual interface also.

switchd currently allows only the standard port 4789 as the UDP port for VXLAN packets. There are cases where a hypervisor could be using non-standard UDP port, which would cause VXLAN exchanges with the hardware VTEP to not work. In such a case, packets would not be terminated and encapsulated packets would be sent out on UDP port 4789.

In Cumulus Linux, if the serial console terminal settings are changed and clocal (modem carrier) is turned off,  systemd may do all of the following:

• Block and stop handling systemctl changes
• Fail to start or restart services
• Prevent reboot and shutdown

For example, running the /usr/bin/reset command may cause this problem when run on the serial console. Once in this state, a new login session will not be started on the serial console (/dev/ttyS0 or ttyS1) after logout, and systemd will not respond to systemctl commands, including reboot.

To work around this issue, whenever you are logged in to the serial console and run reset, run stty clocal afterwards.

When BGP is configured with aggregate addresses with as-set configuration and there are many routes to be aggregated, the BGP process gets into high CPU usage.

To work around this issue, do not specify the as-set parameter for the aggregate-address configuration.

Existing BGP issues caused peering between a VRF device and a loopback BGP session to stay up if the loopback session doesn’t advertise its local address.

This issue will be fixed in a future release.

The rdnbrd service crashes because it cannot work with more than 1024 interfaces.

This issue should be fixed in a future release of Cumulus VX.

Due to hypervisor behavior, upgrades to the grub-pc package may require manual intervention on VX platforms. This is specific to VX and will not occur on hardware platforms.

To resolve the problem, select "/dev/sda" from the interactive menu and continue installation.

When a management VRF was configured using NCLU, the route to the default gateway failed and was considered invalid.

To work around this issue, manually add post-up ip route add vrf mgmt default via IP_ADDRESS to the /etc/network/interfaces file, then run ifreload -a.

If a management VRF if configured, TACACS won't send authentication requests out of the management VRF. Instead, it sends these requests out of the default VRF.

To work around this issue, run the following commands, which restrict inbound SSH to only the management VRF interface and disable inbound SSH via the switch ports. Note that using SSH via the front panel ports is not a workaround.

cumulus@switch:~$ sudo systemctl disable ssh.service
cumulus@switch:~$ sudo systemctl stop ssh.service
cumulus@switch:~$ sudo systemctl enable ssh@mgmt.service
cumulus@switch:~$ sudo systemctl start ssh@mgmt.service