Cisco 801 TX and RX l.e.d's flash every 10 seconds. Why?

[G0AOZ]

This router has been running satisfactorily for about a year, but has suddenly developed a "fault". Dialer idle timeout has always been set at 300 (and still is), and after this period of inactivity the router has previously dropped the line. Without any change of parameters by me, it now stays up all the time, and the TX and RX l.e.d's flash at 10 second intervals ad infinitum even when the connection between router and hub is severed.

What is causing this? I have checked the parmeters (show run) with those when it was set up a year ago, and nothing's changed. Not had any nasty mains power glitches that I'm aware off, and the router still appears to work ok apart from holding up the line all the time.

Has anyone any clues please...?


ROGER - GØAOZ.

 

[svermill]

Well it is odd that something would suddenly change by itself. 10 seconds sounds like keepalives, off hand. But I'm not sure I understand your architecture. What did you mean by "hub?" What kind of interface are we talking about here? How much control do you have over what is on the other end of the router? Is the router doing the dialing, or is it being dialed into?

I guess a little more detail would help us to help you.

Regards,

Scott

 

[G0AOZ]

Ok Scott, thanks for the response... Configuration here is as follows:-

8 PCs running a selection of W95, W98, NT4, W2K linked via Cat5 network system to a 100Mbit hub. Hub links to Cisco 801 router, which is connected to a BT Home Highway ISDN line. No incoming calls - hub instigates dial out. I've a serial link to router console using Hyperterminal.

I'm positively the only one here who has access to the router console, so any "changes" would only have come about as a result of mains power glitches. Only one PC has a UPS, but ALL equipments run through individual good quality voltage spike protectors. No recent electrical storms or power outages, and phone/data lines all run underground here.


ROGER - GØAOZ.

 

[G0AOZ]

And here's another weird thing... Prior to altering anything yesterday evening, I printed off the parameters using "show run", and under Interface Dialer1 it clearly shows dialer idle-timeout 300. I initially altered this down to 60, and Hey Presto! it all works and drops the line, if idle, after 60 seconds.

However, if I now try putting back the time-out as 300, I can save the configuration ok, but it does not appear in the "show run listing, and now of course no longer drops the line. The "cut off" point appears to be 120. If I put in 119 it works and shows in the listing, but put 120 and it doesn't work and doesn't show! Is there another parameter that I need to alter in order to get it to work with idle-timeouts longer than 119 seconds?

Crazy or what...


ROGER - GØAOZ.

 

[svermill]

Crazy indeed! Sounds like a bug but you haven't changed IOS, and it worked before, so that doesn't seem likely. I suppose it's possible something got corrupted, but hopefully there is a more common sense answer than that.

If it comes to it, can you reload or upgrade your IOS? I'm not in favor of just blindly rebooting and reloading stuff, but you seem to have a pretty off-the-wall situation.

I'm leaving civilization for a few days (going into the mountains to watch that Leonid meteor shower and do a little fishing!), so I guess I can't be of much help. Maybe someone else has been up against this?

 

[BuckWeet]

Copy and paste the config, and we can all troubleshoot it..

Are you sure there aren't any PC's that may have trojan horses on it, connecting to the net, to keep the connection up?

BuckWeet

 

[G0AOZ]

Thanks for the reply BuckWeet. Re trojans, no, all PCs run bang up-to-date antivirus software, so I'm sure that's not the answer. Also, having used the internet, I could disconnect the cable between hub and router, and the connection would stay up indefinitely. Here's my current config:-


Current configuration:
!
version 12.0
no service pad
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname ROUTER
!
logging buffered 8192 debugging
enable secret 5 xxxxxxxxxxxxxxxxxxxxxxxxxxxxx.
!
username ROUTER password 7 xxxxxxxxxxxx
!
!
!
!
ip subnet-zero
no ip source-route
!
ip name-server 194.152.64.34
ip name-server 194.152.64.35
ip name-server 194.152.64.68
isdn switch-type basic-net3
!
!
process-max-time 200
!
interface Ethernet0
ip address 10.150.120.154 255.255.255.0
ip access-group 121 in
no ip directed-broadcast
no ip proxy-arp
ip nat inside
!
interface BRI0
no ip address
no ip directed-broadcast
encapsulation ppp
dialer pool-member 1
isdn switch-type basic-net3
ppp authentication chap pap callin
!
interface Dialer1
description ISP
ip address negotiated
ip access-group 121 in
no ip directed-broadcast
no ip proxy-arp
ip nat outside
encapsulation ppp
no ip split-horizon
dialer remote-name Cisco1
dialer idle-timeout 119
dialer string xxxxxxxxxxx class DialClass
dialer hold-queue 10
dialer pool 1
dialer-group 1
pulse-time 0
ppp authentication chap pap callin
ppp chap hostname fred.bloggs.co.uk
ppp chap password 7 xxxxxxxxxxxx
ppp pap sent-username fred.bloggs.co.uk password 7 xxxxxxxxxxxx
!
ip nat inside source list 18 interface Dialer1 overload
no ip http server
ip classless
ip route 0.0.0.0 0.0.0.0 Dialer1
!
!
map-class dialer DialClass
access-list 18 permit 10.0.0.0 0.255.255.255
access-list 121 deny udp any eq netbios-dgm any
access-list 121 deny udp any eq netbios-ns any
access-list 121 deny udp any eq netbios-ss any
access-list 121 deny tcp any eq 137 any
access-list 121 deny tcp any eq 138 any
access-list 121 deny tcp any eq 139 any
access-list 121 permit ip any any time-range TIME
dialer-list 1 protocol ip permit
!
line con 0
exec-timeout 0 0
transport input none
stopbits 1
line vty 0 4
exec-timeout 0 0
login local
!
time-range TIME
periodic daily 0:00 to 23:59
!
end


Note that dialer idle-timeout is currently set to 119, which is the highest setting that appears to "stay" in the config, and that will drop the line satisfactorily. The router interface configuration will accept my original time of 300 seconds when it's typed in, but after saving with "running-config startup-config", the "dialer idle-timeout" line no longer appears in the "show run" config listing, and line stays up indefinitely.


ROGER - GØAOZ.

 

[BuckWeet]

It looks okay to me.. Here's something to do..


Drop the Connection, then initate the command "debug dialer events" (pretty sure thats the command) them sh debug and also "term mon" if you're telneted into the router..

This will show you what traffic it considers interesting and will bring up the circuit... Then just keep monitoring it... You might also need to a the "debug ip packet" after the dialer events command...


BuckWeet