01-29-2003 04:44 AM - edited 03-02-2019 04:38 AM
--begin ciscomoderator note-- The following post has been edited to remove potentially confidential information. Please refrain from posting confidential information on the site to reduce security risks to your network. -- end ciscomoderator note --
Hi Network Professional,
Problem Description:
Cisco 3660 router is not able to PSTN dial up Cisco 805 router, but it works the other way round. Error message "3d00h:
Se0 PPP: Line appears to be looped back" was displayed in Cisco 805's debug output when Cisco 3660 dials into Cisco 805.
The following is configuration:
--------------------cisco 805 start-----------------------------
--moderator edit-- Router1#
--moderator edit-- Router1#sh conf
Using 1296 out of 8060 bytes
!
version 12.0
no service pad
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname --moderator edit-- Router1
!
enable secret 5 --moderator edit--
!
username --moderator edit--password 1 --moderator edit--
ip subnet-zero
!
no ip domain-lookup
chat-script dial "" "AT" OK "ATM0DT\T" TIMEOUT 90 CONNECT \C
!
!
process-max-time 200
!
interface Ethernet0
ip address 10.10.92.1 255.255.255.0
no ip directed-broadcast
!
interface Serial0
physical-layer async
no ip address
no ip directed-broadcast
encapsulation ppp
dialer in-band
dialer pool-member 8
async default routing
async mode dedicated
no fair-queue
ppp authentication chap callin
!
interface Dialer1
ip unnumbered Ethernet0
no ip directed-broadcast
encapsulation ppp
no keepalive
dialer idle-timeout 180
dialer string 768660
dialer pool 8
dialer-group 1
no cdp enable
ppp authentication chap callin
!
no ip http server
ip classless
ip route 0.0.0.0 0.0.0.0 Dialer1 permanent
!
dialer-list 1 protocol ip permit
!
line con 0
password 7 --moderator edit--
login
transport input none
stopbits 1
line 1
modem InOut
modem autoconfigure discovery
transport input all
stopbits 1
speed 115200
flowcontrol hardware
line vty 0 4
password 7 --moderator edit--
login
!
end
--------------------cisco 805 end-------------------------------
--------------------cisco 3660 start-------------------------------
--moderator edit-- Router2#sh conf
Using 3863 out of 129016 bytes
!
version 12.1
no service single-slot-reload-enable
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname --moderator edit-- Router2
!
logging rate-limit console 10 except errors
enable secret 5 --moderator edit--
!
username --moderator edit-- Router1 password 7 --moderator edit--
memory-size iomem 15
ip subnet-zero
!
!
no ip finger
no ip domain-lookup
!
isdn switch-type basic-net3
chat-script async "" "AT" OK "ATDT\T" TIMEOUT 30 CONNECT \C
!
!
!
interface FastEthernet0/0
ip address 10.10.10.1 255.255.192.0
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 10.1.1.2 255.255.255.252
duplex auto
speed auto
!
interface Async97
ip unnumbered FastEthernet0/0
encapsulation ppp
dialer in-band
dialer idle-timeout 180
dialer map ip 10.10.92.1 name --moderator edit-- Router1 modem-script async 772367
dialer-group 1
async mode interactive
ppp authentication chap callin
!
ip classless
ip route 0.0.0.0 0.0.0.0 10.1.1.1 permanent
ip route 10.1.1.0 255.255.255.252 FastEthernet0/1 permanent
ip route 10.10.92.0 255.255.255.0 10.10.92.1
ip route 10.10.92.1 255.255.255.255 Async97
no ip http server
!
dialer-list 1 protocol ip permit
!
line con 0
password 7 --moderator edit--
login
transport input none
line 97 112
autoselect during-login
autoselect ppp
modem InOut
autocommand ppp
stopbits 1
flowcontrol hardware
line aux 0
password 7 --moderator edit--
login
line vty 0 4
timeout login response 10
password 7 --moderator edit--
login
!
end
--------------------cisco 3660 end---------------------------------
Note that in Cisco 3660 router, Async97 is the interface that dial out. Also, Aztech modem is the external modem attached to Cisco 805. Up to this stage, I somehow know that it could be due to the loop in Cisco 805, but has no idea and can't find solution to solve it.
Kindly provide technical advice if you have, I really appreciate it.
Thanks.
01-29-2003 09:04 PM
As it complains, Line is looped. You must be seeing the same MAGIC number during PPP LCP negotiation..So there is a loop in analog circuit path. I think try changing the analog line at 805 side or both the place..
01-30-2003 09:36 PM
Hi tepatel,
Thanks for your reply first.
Actually I found that even the successful dial up, the magic number is also the same. Anyway, I found that line 1 is used in Cisco 805 and line 97 in Cisco 3660, there are already different, so how should I change it?
Thanks.
03-26-2003 09:49 PM
Same Magic number in LCPfrom805 and 3660 side "should" not be the same.
It should be different from both the side according to RFC.
Now i am not clear about what do you want to change about line 97 and line 1. Pl. explain.
03-27-2003 08:57 PM
Hi Tepatel,
I have misunderstood your reply and hence I ask a funny question. In fact so far I have found out the problem is because I do not specify "asyn mode interactive" for serial0 and do not specify "autoselect ppp" for line 1 in Cisco 805 router.
I have simulated in my office and it works fine for me to dial in to Cisco 805 using my notebook. I have requested my customer to test it out and l am waiting his reply.
I will update you once I get the result from him if he still face problem.
Thanks.
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