C-921 Cisco router intermittent internet cut off after some days

[dhaferbk]

I have an intermittent internet cut off after around some days of working (5 to 10 days). The router becomes inaccessible by ssh. No ping also from internet and from inside. The architecture includes two switches (CBS350-48FP-4X) with Vlan1.

We did not find a solution for this issue. This issue started with the first day of this router working. I suspect a physical component problem!

Here is my router running config:

Current configuration : 1878 bytes
!
! Last configuration change at 17:23:04 UTC Tue Apr 2 2024 by admin
!
version 15.8
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname R-0001
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
memory-size iomem 25
!
!
!
!
!
!
!
!
ip dhcp excluded-address 192.168.0.1 192.168.2.255
ip dhcp excluded-address 192.168.5.0 192.168.255.255
!
ip dhcp pool mainPool
import all
network 192.168.0.0 255.255.0.0
default-router 192.168.2.1
dns-server 192.168.2.1
!
!
!
ip domain name geniacom.com
ip name-server 198.154.101.1
ip name-server 198.231.100.1
ip cef
no ipv6 cef
multilink bundle-name authenticated
!
!
!
license udi pid C921-4P sn PSZ27421DXZ
!
!
!
redundancy
!
!
!
!
!
!
interface GigabitEthernet0
no ip address
!
interface GigabitEthernet1
no ip address
!
interface GigabitEthernet2
no ip address
!
interface GigabitEthernet3
no ip address
!
interface GigabitEthernet4
ip address 55.71.7.250 255.255.255.248
ip nat outside
ip virtual-reassembly in
duplex auto
speed auto
!
interface GigabitEthernet5
no ip address
shutdown
duplex auto
speed auto
!
interface Vlan1
ip address 192.168.2.1 255.255.0.0
ip nat inside
ip virtual-reassembly in
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
ip dns server
ip nat inside source list 1 interface GigabitEthernet4 overload
ip route 0.0.0.0 0.0.0.0 GigabitEthernet4 55.71.7.249
!
!
!
access-list 1 permit 192.168.0.0 0.0.255.255
access-list 101 permit udp any any eq domain
access-list 101 permit udp any eq domain any
!
control-plane
!
!
line con 0
login
line vty 0 4
login local
transport input ssh
!
scheduler allocate 20000 1000
!
end

R-0001#show interfaces GigabitEthernet 4
GigabitEthernet4 is up, line protocol is up
Hardware is iGbE, address is ecf4.0c78.aaa4 (bia ecf4.0c78.aaa4)
Internet address is 55.71.7.250/29
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 2/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full Duplex, 1Gbps, media type is RJ45
output flow-control is XON, input flow-control is XON
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 4299000 bits/sec, 1072 packets/sec
5 minute output rate 10279000 bits/sec, 1254 packets/sec
25351162 packets input, 17258219706 bytes, 0 no buffer
Received 22509 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 503 multicast, 0 pause input
22186270 packets output, 21911522023 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
503 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
1 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out

R-0001#show ip interface GigabitEthernet 4
GigabitEthernet4 is up, line protocol is up
Internet address is 55.71.7.250/29
Broadcast address is 255.255.255.255
Address determined by non-volatile memory
MTU is 1500 bytes
Helper address is not set
Directed broadcast forwarding is disabled
Outgoing access list is not set
Inbound access list is not set
Proxy ARP is enabled
Local Proxy ARP is disabled
Security level is default
Split horizon is enabled
ICMP redirects are always sent
ICMP unreachables are always sent
ICMP mask replies are never sent
IP fast switching is enabled
IP fast switching on the same interface is disabled
IP Flow switching is disabled
IP CEF switching is enabled
IP CEF switching turbo vector
IP multicast fast switching is enabled
IP multicast distributed fast switching is disabled
IP route-cache flags are Fast, CEF
Router Discovery is disabled
IP output packet accounting is disabled
IP access violation accounting is disabled
TCP/IP header compression is disabled
RTP/IP header compression is disabled
Policy routing is disabled
Network address translation is enabled, interface in domain outside
BGP Policy Mapping is disabled
Input features: Common Flow Table, Stateful Inspection, Virtual Fragment Reassembly, Virtual Fragment Reassembly After IPSec Decryption, NAT Outside, MCI Check
Output features: Post-routing NAT Outside, Common Flow Table, Stateful Inspection, NAT ALG proxy
IPv4 WCCP Redirect outbound is disabled
IPv4 WCCP Redirect inbound is disabled
IPv4 WCCP Redirect exclude is disabled

R-0001#show interfaces GigabitEthernet 0
GigabitEthernet0 is up, line protocol is up
Hardware is Gigabit Ethernet, address is ecf4.0c78.aaa0 (bia ecf4.0c78.aaa0)
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 2/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:01, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 9747000 bits/sec, 1229 packets/sec
5 minute output rate 4093000 bits/sec, 1043 packets/sec
22929781 packets input, 22307384131 bytes, 0 no buffer
Received 130915 broadcasts (238063 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
0 input packets with dribble condition detected
25687060 packets output, 17551904558 bytes, 0 underruns
0 output errors, 0 collisions, 2 interface resets
503 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out\

R-0001#show interfaces Vlan 1
Vlan1 is up, line protocol is up
Hardware is EtherSVI, address is ecf4.0c78.aaa0 (bia ecf4.0c78.aaa0)
Internet address is 192.168.2.1/16
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 2/255
Encapsulation ARPA, loopback not set
Keepalive not supported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 9025000 bits/sec, 1145 packets/sec
5 minute output rate 3706000 bits/sec, 990 packets/sec
23011748 packets input, 22311987645 bytes, 0 no buffer
Received 131750 broadcasts (25459 IP multicasts)
0 runts, 0 giants, 31 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
25779299 packets output, 17483698251 bytes, 0 underruns
0 output errors, 1 interface resets
104371 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out

R-0001#show ip interface Vlan 1
Vlan1 is up, line protocol is up
Internet address is 192.168.2.1/16
Broadcast address is 255.255.255.255
Address determined by non-volatile memory
MTU is 1500 bytes
Helper address is not set
Directed broadcast forwarding is disabled
Outgoing access list is not set
Inbound access list is not set
Proxy ARP is enabled
Local Proxy ARP is disabled
Security level is default
Split horizon is enabled
ICMP redirects are always sent
ICMP unreachables are always sent
ICMP mask replies are never sent
IP fast switching is enabled
IP fast switching on the same interface is disabled
IP Flow switching is disabled
IP CEF switching is enabled
IP CEF switching turbo vector
IP Null turbo vector
IP multicast fast switching is enabled
IP multicast distributed fast switching is disabled
IP route-cache flags are Fast, CEF
Router Discovery is disabled
IP output packet accounting is disabled
IP access violation accounting is disabled
TCP/IP header compression is disabled
RTP/IP header compression is disabled
Policy routing is disabled
Network address translation is enabled, interface in domain inside
BGP Policy Mapping is disabled
Input features: Common Flow Table, Stateful Inspection, Virtual Fragment Reassembly, Virtual Fragment Reassembly After IPSec Decryption, MCI Check
Output features: NAT Inside, Common Flow Table, Stateful Inspection, NAT ALG proxy
IPv4 WCCP Redirect outbound is disabled
IPv4 WCCP Redirect inbound is disabled
IPv4 WCCP Redirect exclude is disabled

The running config of switches:

config-file-header
W-0001
v3.2.1.1 / RCBS3.2hotfix_950_377_136
CLI v1.0
file SSD indicator encrypted
@
ssd-control-start
ssd config
ssd file passphrase control unrestricted
no ssd file integrity control
ssd-control-end cb0a3fdb1f3a1af4e4430033719968c0
!
!
unit-type-control-start
unit-type unit 1 network gi uplink te
unit-type unit 2 network gi uplink te
unit-type unit 3 network gi uplink te
unit-type unit 4 network gi uplink te
unit-type-control-end
!
voice vlan oui-table add 0001e3 Siemens_AG_phone
voice vlan oui-table add 00036b Cisco_phone
voice vlan oui-table add 00096e Avaya
voice vlan oui-table add 000fe2 H3C_Aolynk
voice vlan oui-table add 0060b9 Philips_and_NEC_AG_phone
voice vlan oui-table add 00d01e Pingtel_phone
voice vlan oui-table add 00e075 Polycom/Veritel_phone
voice vlan oui-table add 00e0bb 3Com_phone
bonjour interface range vlan 1
hostname W-0001
logging file informational
logging aggregation on
ip ssh server
snmp-server location Rack1-Level2

clock timezone EST -5
clock summer-time web recurring usa
ip telnet server
!
interface vlan 1
ip address 192.168.2.2 255.255.0.0
no ip address dhcp
!
exit
ip default-gateway 192.168.2.1

[balaji.bandi]

other than some unknow protocol drops i do not see any obvious.

how are you resolving the issue, by rebooting the router ?

before rebooting the router, connect to console to router and collect logs and also check the CPU process ?

also directly connect device to router and see if that is working as expected ? (avoid going via switch ?)

show nat translation also check same time.

Also try using Public DNS Server or provider DNS Serer see that makes any difference ?

if the IP not changing you can change from : (this not cause issue good to make best practice).

ip route 0.0.0.0 0.0.0.0 GigabitEthernet4 55.71.7.249

to 

ip route 0.0.0.0 0.0.0.0  55.71.7.249