Cisco 1720 slows and then jams 1

[Wildeep]

I am running a T1 in to a 1720 cisco router. same config for 4 years now. now several times per day the internet connection slows with DNS errors and finally comes to a halt.
If I have an excisting connection open I still have activity such as a chat server. but any new connections to other pages fails.
seems like DNS issues but unsure how to troubleshoot the router. the only fix I have is to restart the router which clears everything up for a few hours.

Also during the night and weekends there is no issues.

Thanks in advance for any help you may offer.

eep eep

 

[JOAMON]

Can you post the config with passwords removed?

 

[MartinR82]

Definately need to see the config.

 

[Wildeep]

Here is the config.

show config
Using 1598 out of 29688 bytes
!
version 12.2
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname Accutech1720
!
boot system flash:c1700-y-mz.122-4.T1.bin
enable secret
enable password
!
memory-size iomem 15
ip subnet-zero
ip name-server 65.106.1.196
ip name-server 65.106.7.196
ip dhcp excluded-address 192.168.1.1 192.168.1.99
ip dhcp excluded-address 192.168.1.201 192.168.1.254
!
ip dhcp pool
network 192.168.1.0 255.255.255.0
domain-name accutechpkg.com
default-router 192.168.1.1
netbios-name-server 192.168.1.3
netbios-node-type h-node
dns-server 65.106.1.196 65.106.7.196
!
!
!
!
interface Ethernet0
ip address 66.238.225.30 255.255.255.240
ip nat outside
half-duplex
!
interface FastEthernet0
ip address 192.168.1.1 255.255.255.0
ip nat inside
speed auto
full-duplex
!
interface Serial0
no ip address
shutdown
!
ip nat inside source list 1 interface Ethernet0 overload
ip nat inside source static 192.168.1.254 66.238.225.28 extendable
ip nat inside source static 192.168.1.3 66.238.225.19 extendable
ip nat inside source static 192.168.1.28 66.238.225.20 extendable
ip nat inside source static 192.168.1.25 66.238.225.25 extendable
ip nat inside source static 192.168.1.26 66.238.225.26 extendable
ip nat inside source static 192.168.1.27 66.238.225.27 extendable
ip classless
ip route 0.0.0.0 0.0.0.0 66.238.225.18
no ip http server
!
access-list 1 permit 192.168.1.0 0.0.0.255
!
line con 0
speed 115200
line aux 0
line vty 0 4

 

[JOAMON]

Couple things I would check. Do a show interface etherrnet0 and look at the stats for errors. What might be a problem, but maybe not the complete problem, is that this interface is set to half duplex and is only capable of speed of 10. I have seen it were duplex and speed mismatch errors can affect your performance. Try setting the interface to full duplex and see if that helps. If you are having problems you can watch for them by telnetting into the router and the entering terminal monitor and the console errors will flash on the screen.

 

[Wildeep]

Thanks for the idea JOAMON. I will change the config to full duplex.

How do I enter terminal monitor via telnet?

here is the results from show ethernet0

show interface ethernet0
Ethernet0 is up, line protocol is up
Hardware is PQUICC Ethernet, address is 0004.dd0c.d3fe (bia 0004.dd0c.d3fe)
Internet address is 66.238.225.30/28
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,
reliability 255/255, txload 2/255, rxload 2/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Half-duplex, 10BaseT
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
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 104000 bits/sec, 36 packets/sec
5 minute output rate 98000 bits/sec, 94 packets/sec
245588 packets input, 59611731 bytes, 0 no buffer
Received 522 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
755143 packets output, 88358787 bytes, 0 underruns
1547 output errors, 2360 collisions, 1 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out

 

[JOAMON]

From the router# prompt just type
terminal monitor

If using a console cable connection they will automatically display.

After changing the duplex setting ffrom the router# prompt type
clear counters to reset the counters.......monitor the interface and watch for errors. You will see the collisions go away but what you dont want to see is CRC errors.

 

[Wildeep]

Another show

show interface ethernet0
Ethernet0 is up, line protocol is up
Hardware is PQUICC Ethernet, address is 0004.dd0c.d3fe (bia 0004.dd0c.d3fe)
Internet address is 66.238.225.30/28
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Half-duplex, 10BaseT
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
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 75000 bits/sec, 24 packets/sec
5 minute output rate 34000 bits/sec, 47 packets/sec
587159 packets input, 145793877 bytes, 0 no buffer
Received 1288 broadcasts, 0 runts, 0 giants, 0 throttles
1015 input errors, 457 CRC, 557 frame, 0 overrun, 1 ignored
0 input packets with dribble condition detected
1631489 packets output, 186689590 bytes, 1 underruns
2832 output errors, 4355 collisions, 9 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out

 

[JOAMON]

That is much worse...I would change it back as you are now getting CRC errors. What make and model device is ethernet 0 connecting to??

 

[JOAMON]

Wait....it still shows in the output as half duplex...didnt you change it? If so then shutdown the interface and then bring it back up for the new settings to take affect. Also do a clear counters to reset the interface counters

 

[tech1994]

Have you tried to enable logging and viewing logged messages? Syslog would also fit the bill, setup a syslog server. I think Kiwi has a free one.

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