1751 intermittent problems with Linux clients

[JPWillis]

Hello all,

I've been beating my brain over a problem with my Cisco 1751. It serves as my ADSL modem and external router for my network.
The problem is this:

Windows and Mac OS X machines can consistently access Internet sites through it, as well as being able to telnet to it. Linux machines (and other non-Windows, non-Mac OS X machines) have an intermittent problem where they can always receive ping responses from the 1751, but not telnet to it or access Internet sites through it. Sometimes, a Linux machine will have Internet access through it, and then seem to randomly lose it, and sometimes, Linux machines will take 20-30 minutes to be able to access the Internet through it, just by letting them sit there. The problem affects Ubuntu 12.04, CentOS 5, CentOS 6, Slackware 13.37, NetBSD, and OS/2 Warp. Have had no such problem with Windows 7.

The problem seems to affect freshly-installed Ubuntu 12.04 and CentOS 5/6 machines, as well as those that have been customized, whether running on bare hardware or as Xen guests.

Here's the output of "show hardware" in enable mode:

Cisco Internetwork Operating System Software
IOS (tm) C1700 Software (C1700-SY7-M), Version 12.3(9), RELEASE SOFTWARE (fc2)
Copyright (c) 1986-2004 by cisco Systems, Inc.
Compiled Fri 14-May-04 15:39 by dchih
Image text-base: 0x80008120, data-base: 0x80DDF300


ROM: System Bootstrap, Version 12.2(7r)XM2, RELEASE SOFTWARE (fc1)


CLOGIC_ERTR uptime is 19 minutes
System returned to ROM by reload at 22:23:19 UTC Sun Jul 14 2013
System restarted at 13:27:05 UTC Sun Jul 14 2013
System image file is "flash:c1700-sy7-mz.123-9.bin"


cisco 1751-V (MPC860P) processor (revision 0x600) with 82402K/15902K bytes of memory.
Processor board ID FOC09303CCA (3736323519), with hardware revision 0000
MPC860P processor: part number 5, mask 2
Bridging software.
X.25 software, Version 3.0.0.
1 FastEthernet/IEEE 802.3 interface(s)
1 ATM network interface(s)
32K bytes of non-volatile configuration memory.
32768K bytes of processor board System flash (Read/Write)


Configuration register is 0x2102


Here's the output of "sh conf", also in enable mode:


Using 6793 out of 29688 bytes
!
! Last configuration change at 14:19:15 UTC Sun Jul 14 2013
! NVRAM config last updated at 14:19:29 UTC Sun Jul 14 2013
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname CLOGIC_ERTR
!
boot-start-marker
boot system flash:c1700-sy7-mz.124-1a.bin
boot-end-marker
!
enable secret 5 xxxxxxxxxxxxxxxxxxxxxxxxxx
!
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
no aaa new-model
no ip subnet-zero
!
!
!
ip cef
!
!
!
!
interface ATM0/0
no ip address
no ip mroute-cache
no atm ilmi-keepalive
dsl operating-mode auto
hold-queue 224 in
pvc 0/32
encapsulation aal5mux ppp dialer
dialer pool-member 1
!
!
interface FastEthernet0/0
ip address 10.0.0.1 255.0.0.0
ip nat inside
no ip mroute-cache
speed auto
full-duplex
!
interface Dialer0
ip address xxx.xxx.xxx.xxx 255.255.255.240
ip nat outside
encapsulation ppp
dialer pool 1
dialer-group 1
ppp authentication chap pap callin
ppp chap hostname xxxxxxxxxxxxxx
ppp chap password 0 xxxxxxxxx
ppp pap sent-username xxxxxxxxx password 0 xxxxxxx
!
router rip
version 2
redistribute static
network 10.0.0.0
default-metric 2
!
ip nat inside source list 5 interface Dialer0 overload
ip nat inside source static tcp x.x.x.x 22 x.x.x.x 22 extendable
ip classless
ip route 0.0.0.0 0.0.0.0 Dialer0
no ip http server
!
!
access-list 5 permit 10.0.0.0 0.255.255.255
dialer-list 1 protocol ip permit
!
snmp-server community logicnet RO
snmp-server enable traps tty
banner motd ^C
^C
!
line con 0
line aux 0
line vty 0 4
password xxxxx
login
!
end

There is a WIC-1ADSL in the chassis (ATM0/0) as well as the built-in Ethernet port.
Any ideas or pointers?
Thanks much in advance,
jpw

 

[baddos]

What are the IP addresses of those clients affected? Also, not relating to your problem but the fastethernet0/0 interface will have a speed and duplex mismatch with that configuration. If you want the speed to be set to auto, the duplex should be as well.

 

[Viconsul]

Hi,

1. Compare the ip configuration and setting of the linux hosts with the working windows hosts.
2. How are they connected to the router? My assumption is that you have a switch connecting them.
3. If line 2 above is correct then check the switch ports and try swapping the hosts around.
4. Check that you don't have any access-list blocking the linux hosts
5. Also, try swapping the ip addresses around, i.e change windows host ip to linux host ip and vice versa.