cisco 1721 internet problem

[mannybabe]

i have a 1721 router connected to a 3com superstack switch. i have a dsl modem connected to one of the ethernet ports on the cisco router. Periodically the internet will go down. When you restart a pc it takes awhile for it to get on the internet. Whenever the internet is down i am able to ping the default gateway on the router but it pings at 150ms then i notice whenever the internet is working it pings at 255ms. This holds true for every pc. some pc's will have internet some won't. if the ping of the gateway is 150 i can't telnet to it once it's 255 i can telnet to it. For those pc's that don't have inter i have to either wait for like 2 minutes or telnet to the router from a machine that has internet and ping the ip address of the machine that doesn't from the router. Then the internet works

 

[lui3]

can you post your configuration and a show interface on the ethernet interface that is connecting to your superstack switch.

 

[mannybabe]

Building configuration...

Current configuration : 3951 bytes
!
version 12.2
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname pbpmc
!
enable secret 5 $1$Tx61$2Cs/Wtg4NrGFhLLZGqggG0
!
ip subnet-zero
!
ip audit notify log
ip audit po max-events 100
!
!
!
!
interface Ethernet0/0
ip address 207.40.20.215 255.255.255.128
ip nat outside
full-duplex
!
interface FastEthernet0/0
ip address 192.168.144.1 255.255.255.0
ip nat inside
speed auto
!
ip nat pool pbpmc 207.40.20.215 207.40.20.215 netmask 255.255.255.128
ip nat inside source list 3 pool pbpmc overload
ip nat inside source static udp 192.168.144.132 5634 interface Ethernet0/0 5634
ip nat inside source static udp 192.168.144.132 5633 interface Ethernet0/0 5633
ip nat inside source static tcp 192.168.144.137 21 interface Ethernet0/0 21
ip nat inside source static udp 192.168.144.200 22 interface Ethernet0/0 22
ip nat inside source static tcp 192.168.144.200 22 interface Ethernet0/0 22
ip nat inside source static tcp 192.168.144.100 5631 interface Ethernet0/0 5631
ip nat inside source static udp 192.168.144.100 5631 interface Ethernet0/0 5631
ip nat inside source static tcp 192.168.144.100 5632 interface Ethernet0/0 5632
ip nat inside source static udp 192.168.144.100 5632 interface Ethernet0/0 5632
ip nat inside source static tcp 192.168.144.100 1723 interface Ethernet0/0 1723
ip nat inside source static udp 192.168.144.100 1723 interface Ethernet0/0 1723
ip nat inside source static tcp 192.168.144.200 23 interface Ethernet0/0 23
ip nat inside source static udp 192.168.144.200 23 interface Ethernet0/0 23
ip nat inside source static tcp 192.168.144.122 3389 interface Ethernet0/0 3389
ip nat inside source static udp 192.168.144.122 3389 interface Ethernet0/0 3389
ip nat inside source static tcp 192.168.144.122 1043 interface Ethernet0/0 1043
ip nat inside source static udp 192.168.144.122 1044 interface Ethernet0/0 1044
ip nat inside source static udp 192.168.144.122 1043 interface Ethernet0/0 1043
ip nat inside source static tcp 192.168.144.122 1044 interface Ethernet0/0 1044
ip nat inside source static tcp 192.168.144.122 1045 interface Ethernet0/0 1045
ip nat inside source static udp 192.168.144.122 1045 interface Ethernet0/0 1045
ip nat inside source static tcp 192.168.144.122 1046 interface Ethernet0/0 1046
ip nat inside source static udp 192.168.144.122 1046 interface Ethernet0/0 1046
ip nat inside source static tcp 192.168.144.122 1047 interface Ethernet0/0 1047
ip nat inside source static udp 192.168.144.122 1047 interface Ethernet0/0 1047
ip nat inside source static tcp 192.168.144.122 1048 interface Ethernet0/0 1048
ip nat inside source static udp 192.168.144.122 1048 interface Ethernet0/0 1048
ip nat inside source static tcp 192.168.144.122 1049 interface Ethernet0/0 1049
ip nat inside source static udp 192.168.144.122 1049 interface Ethernet0/0 1049
ip nat inside source static tcp 192.168.144.122 1050 interface Ethernet0/0 1050
ip nat inside source static udp 192.168.144.122 1050 interface Ethernet0/0 1050
ip nat inside source static tcp 192.168.144.200 20 interface Ethernet0/0 20
ip nat inside source static udp 192.168.144.200 20 interface Ethernet0/0 20
ip nat inside source static tcp 192.168.144.132 5633 interface Ethernet0/0 5633
ip nat inside source static tcp 192.168.144.132 5634 interface Ethernet0/0 5634
ip nat inside source static tcp 192.168.144.155 5635 interface Ethernet0/0 5635
ip nat inside source static tcp 192.168.144.155 5636 interface Ethernet0/0 5636
ip nat inside source static udp 192.168.144.155 5635 interface Ethernet0/0 5635
ip nat inside source static udp 192.168.144.155 5636 interface Ethernet0/0 5636
ip classless
ip route 0.0.0.0 0.0.0.0 207.40.20.129
no ip http server
!
!
logging facility local0
logging 192.168.144.137
access-list 3 permit 192.168.144.0 0.0.0.255
!
line con 0
password
login
line aux 0
password
login
line vty 0 4
password
login
!
end


SHOW INTERFACE ETHERNET0/0
Ethernet0/0 is up, line protocol is up
Hardware is PQUICC Ethernet, address is 0004.dd0d.116f (bia 0004.dd0d.116f)
Internet address is 207.40.20.215/25
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,
reliability 255/255, txload 1/255, rxload 6/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 10BaseT
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:03, 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 274000 bits/sec, 28 packets/sec
5 minute output rate 18000 bits/sec, 24 packets/sec
6448616 packets input, 1609794747 bytes, 0 no buffer
Received 44569 broadcasts, 0 runts, 24 giants, 0 throttles
24242 input errors, 12182 CRC, 12036 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
6159316 packets output, 1627474625 bytes, 0 underruns
0 output errors, 0 collisions, 2 interface resets
0 babbles, 0 late collision, 0 deferred
Hardware is PQUICC Ethernet, address is 0004.dd0d.116f (bia 0004.dd0d.116f)
Internet address is 207.40.20.215/25
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,
reliability 255/255, txload 1/255, rxload 6/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 10BaseT
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:03, 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 274000 bits/sec, 28 packets/sec
5 minute output rate 18000 bits/sec, 24 packets/sec
6448616 packets input, 1609794747 bytes, 0 no buffer
Received 44569 broadcasts, 0 runts, 24 giants, 0 throttles
24242 input errors, 12182 CRC, 12036 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
6159316 packets output, 1627474625 bytes, 0 underruns
0 output errors, 0 collisions, 2 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out


whoop there it is

 

[lui3]

24242 input errors, 12182 CRC, 12036 frame, 0 overrun, 0 ignored

Thats a lot of interface errors on the ethernet port. Check the duplex settings at both ends and make sure they are set the same full to full or auto to auto. Mixed ones have problems. Also check the cable.

Also can you issue a

clear counters interface ether0/0

so we can see if the errors are still occuring.

full-duplex (is there are reason for setting this statically. is the dsl modem set statically as well or is it autonegotiating. this can cause big throughput problems if one side if 10 full and the other is mismatched. )

check it out and let me know.

you always set the ether 0/0 to speed auto duplex auto and see if it connects to the modem without errors.

 

[mannybabe]

how do i check what mode my dsl modem is (full duplex or auto) that is what is connected to my ether0/0 interface. It's a static ip address on the dsl modem

 

[mannybabe]

how do i check what mode my dsl modem is (full duplex or auto) that is what is connected to my ether0/0 interface. It's a static ip address on the dsl modem. how do i set speed to auto and duplex to auto?

 

[lui3]

i would assume it is auto. set you cisco interface to auto and see what it negotiates. if it negotiates 100 base full duplex then the dsl modem is auto. if it negotiates 100 half then the dsl modem is set to 100 full and you need to set your cisco side 100 full.

 

[lui3]

on the cisco router you can set the speed using the following interface configuration commands

router(config)#interface ether 0/0
router(config-if)#no speed full
router(config-if)#no duplex full

or

router(config-if)#default speed
router(config-if)#default duplex

the order is important. i can't remember which one comes first. i think its speed. anyways if you do it in the wrong order the IOS will tell you and give you an error message.