Interface goes down after 2 minutes

Junaid_Subhani · January 21, 2015, 9:30am

Hi all,

I am using an F5 LTM Load balancer VM. Its network config is as follows:

eth0      Link encap:Ethernet  HWaddr 00:50:56:01:01:FA  
          inet addr:192.168.2.104  Bcast:192.168.2.255  Mask:255.255.255.0
          inet6 addr: fe80::250:56ff:fe01:1fa/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:7134 errors:0 dropped:0 overruns:0 frame:0
          TX packets:70 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:431545 (421.4 KiB)  TX bytes:9888 (9.6 KiB)

eth1      Link encap:Ethernet  HWaddr 00:50:56:01:01:FB  
          inet6 addr: fe80::250:56ff:fe01:1fb/64 Scope:Link
          UP BROADCAST RUNNING PROMISC ALLMULTI MULTICAST  MTU:1500  Metric:1
          RX packets:479497 errors:0 dropped:0 overruns:0 frame:0
          TX packets:7 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:38422565 (36.6 MiB)  TX bytes:810 (810.0 b)

eth2      Link encap:Ethernet  HWaddr 00:50:56:01:01:F8  
          inet6 addr: fe80::250:56ff:fe01:1f8/64 Scope:Link
          UP BROADCAST RUNNING PROMISC ALLMULTI MULTICAST  MTU:1500  Metric:1
          RX packets:457477 errors:0 dropped:0 overruns:0 frame:0
          TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:34193855 (32.6 MiB)  TX bytes:468 (468.0 b)

eth3      Link encap:Ethernet  HWaddr 00:50:56:01:01:FC  
          inet addr:142.133.174.246  Bcast:142.133.175.255  Mask:255.255.254.0
          inet6 addr: fe80::250:56ff:fe01:1fc/64 Scope:Link
          UP BROADCAST RUNNING PROMISC ALLMULTI MULTICAST  MTU:1500  Metric:1
          RX packets:459573 errors:0 dropped:0 overruns:0 frame:0
          TX packets:305 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:34535062 (32.9 MiB)  TX bytes:30038 (29.3 KiB)

eth4      Link encap:Ethernet  HWaddr 00:50:56:01:01:F9  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.255.255.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:34913 errors:0 dropped:0 overruns:0 frame:0
          TX packets:34913 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:2886349 (2.7 MiB)  TX bytes:2886349 (2.7 MiB)

lo:1      Link encap:Local Loopback  
          inet addr:127.2.0.2  Mask:255.255.255.0
          UP LOOPBACK RUNNING  MTU:16436  Metric:1

mgmt_bp   Link encap:IPIP Tunnel  HWaddr   
          inet addr:127.3.0.0  Mask:255.255.255.255
          UP RUNNING NOARP  MTU:1480  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:8 dropped:0 overruns:0 carrier:8
          collisions:0 txqueuelen:0 
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

tmm0      Link encap:Ethernet  HWaddr 00:98:76:54:32:10  
          inet addr:127.1.1.1  Bcast:127.1.1.255  Mask:255.255.255.0
          inet6 addr: fe80::298:76ff:fe54:3210/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:9198  Metric:1
          RX packets:4318 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4297 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:255977 (249.9 KiB)  TX bytes:710130 (693.4 KiB)

It is connected to other RHEL VMs using 2 networks, 192.168.2.X & 142.133.174.X .

Once I boot the F5 VM up, I am able to ping the default gateway of the 142.133.174.X network for about 2 minutes after which the ping fails;

[root@localhost:Offline:Standalone] config # ping 142.133.174.1
PING 142.133.174.1 (142.133.174.1) 56(84) bytes of data.
From 142.133.174.246 icmp_seq=2 Destination Host Unreachable
From 142.133.174.246 icmp_seq=3 Destination Host Unreachable
From 142.133.174.246 icmp_seq=4 Destination Host Unreachable

Using an other VM on the 142.133.174.X network, I cannot ping the F5 VM.

When I send the reboot command, the ping again starts to be successful.

I have no idea why the network ( 142.133.174.X ) or the interface is acting this way.

Any idea ?

[root@localhost:Offline:Standalone] config # ip route
127.1.1.0/24 dev tmm0  proto kernel  scope link  src 127.1.1.1 
127.3.0.0/24 dev mgmt_bp  scope link 
192.168.2.0/24 dev eth0  proto kernel  scope link  src 192.168.2.104 
142.133.174.0/23 dev eth3  proto kernel  scope link  src 142.133.174.246 
default via 142.133.174.1 dev eth3

dmesg output

loop: module loaded
ip_tables: (C) 2000-2006 Netfilter Core Team
nf_conntrack version 0.5.0 (16384 buckets, 65536 max)
warning: `mcstransd' uses 32-bit capabilities (legacy support in use)
eth0: intr type 3, mode 0, 3 vectors allocated
eth0: NIC Link is Up 10000 Mbps
eth1: intr type 3, mode 0, 3 vectors allocated
eth1: NIC Link is Up 10000 Mbps
eth2: intr type 3, mode 0, 3 vectors allocated
eth2: NIC Link is Up 10000 Mbps
eth3: intr type 3, mode 0, 3 vectors allocated
eth3: NIC Link is Up 10000 Mbps
ADDRCONF(NETDEV_UP): eth4: link is not ready
IPv4 over IPv4 tunneling driver
tunl0: Disabled Privacy Extensions
mgmt_bp: Disabled Privacy Extensions
eth0: no IPv6 routers present
eth1: no IPv6 routers present
eth2: no IPv6 routers present
eth3: no IPv6 routers present
SELinux: initialized (dev hda1, type vfat), uses genfs_contexts
vnic: control interface intialized
SELinux: initialized (dev hda1, type vfat), uses genfs_contexts
vnic: register instance 0
[built:14:45:06][unic] handle_unic_mmap(674): size=327680, start=47530241994752, end=47530242322432, type=0
[built:14:45:06][unic] handle_unic_mmap(674): size=327680, start=47530242322432, end=47530242650112, type=128
device eth3 entered promiscuous mode
[built:14:45:06][unic] unic_cmp_addunic(1301): TMM CMP index 0, device eth3
[built:14:45:06][unic] handle_unic_mmap(674): size=327680, start=47530242650112, end=47530242977792, type=0
[built:14:45:06][unic] handle_unic_mmap(674): size=327680, start=47530242977792, end=47530243305472, type=128
device eth1 entered promiscuous mode
[built:14:45:06][unic] unic_cmp_addunic(1301): TMM CMP index 0, device eth1
[built:14:45:06][unic] handle_unic_mmap(674): size=327680, start=47530243305472, end=47530243633152, type=0
[built:14:45:06][unic] handle_unic_mmap(674): size=327680, start=47530243633152, end=47530243960832, type=128
device eth2 entered promiscuous mode
[built:14:45:06][unic] unic_cmp_addunic(1301): TMM CMP index 0, device eth2

Corona688 · January 21, 2015, 10:27am

What interface is this? Something like a packet sniffer is messing with it.

Junaid_Subhani · January 21, 2015, 11:24am

Its just a simple interface used to access the node. I dont think any sniffing is going on.

Corona688 · January 21, 2015, 11:43am

Something is, though. That's what "promiscuous mode" means, it will receive packets to any destination. Things like wireshark and tcpdump use it to monitor the connection.

What programs / services are you running? You need to find what is putting it into that mode. Whatever it is, is what I suspect is messing up your connection.