you might have hit that on the head.
I have drawn a simple diagram. The netw was ok using a now disconnected 2 meg serial link. The 2600 other serial supports a dlsw controller. The c/m connected a 100 meg base tx ther are two vlans on the and the 4k router is routing them see cfg below.
I have found out that from the 4k router I can ping any size at all to a server 10.142.232.1, but from the cat 4k switch an extended ping fails with >1470 bytes. At the bottom I have appended the dlsw roter config.
Dawson_RD_L3_Router#sh run
Building configuration...
Current configuration:
!
version 12.0
no service pad
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname Dawson_RD_L3_Router
!
!
ip subnet-zero
no ip domain-lookup
bridge irb
!
!
!
interface Loopback0
ip address 10.254.250.18 255.255.255.255
no ip directed-broadcast
!
interface Port-channel1
no ip address
no ip directed-broadcast
hold-queue 300 in
!
interface Port-channel1.1
bandwidth 100000
encapsulation dot1Q 1 native
ip address 10.10.97.7 255.255.224.0
no ip redirects
no ip directed-broadcast
!
interface Port-channel1.2
bandwidth 100000
encapsulation dot1Q 144
ip address 10.144.129.49 255.255.252.0
ip helper-address 10.144.129.50
ip helper-address 10.40.195.7
no ip redirects
no ip directed-broadcast
!
interface FastEthernet1
ip address 10.142.233.48 255.255.252.0 secondary
ip address 10.142.233.49 255.255.252.0
no ip directed-broadcast
speed 100
full-duplex
!
interface FastEthernet1.1
no ip directed-broadcast
!
interface GigabitEthernet1
no ip address
no ip directed-broadcast
shutdown
!
interface GigabitEthernet2
no ip address
no ip directed-broadcast
shutdown
!
interface GigabitEthernet3
no ip address
no ip directed-broadcast
no negotiation auto
channel-group 1
!
interface GigabitEthernet4
no ip address
no ip directed-broadcast
no negotiation auto
channel-group 1
!
router eigrp 1
redistribute static
passive-interface FastEthernet1
network 10.0.0.0
!
ip classless
no ip forward-protocol udp netbios-ns
no ip forward-protocol udp netbios-dgm
ip route 10.254.251.84 255.255.255.255 FastEthernet1
!
end
Dawson_RD_L3_Router#
User Access Verification
Password:
Dawson_Rd>en
Password:
Dawson_Rd#=
% Unknown command or computer name, or unable to find computer address
Dawson_Rd#sh run
Building configuration...
Current configuration:
!
version 11.2
service password-encryption
no service udp-small-servers
no service tcp-small-servers
!
hostname Dawson_Rd
!
!
no ip domain-lookup
ipx routing 00e0.f759.bc4c
dlsw local-peer peer-id 10.254.251.84
dlsw remote-peer 0 tcp 10.254.251.30
!
interface Loopback0
ip address 10.254.251.84 255.255.255.255
!
interface Ethernet0
description Local Hub
ip address 10.142.233.43 255.255.252.0
ip helper-address 10.40.195.7
ipx network 142232B0
!
interface Serial0
description 2 Meg To L.R.H.
ip unnumbered Loopback0
encapsulation ppp
bandwidth 2000
shutdown
ipx network 142232B1
no fair-queue
!
interface Serial1
description IBM Controller DAW4
no ip address
encapsulation sdlc
bandwidth 64000
no keepalive
clockrate 64000
sdlc role primary
sdlc vmac b254.2510.8400
sdlc poll-pause-timer 200
sdlc address 01
sdlc xid 01 01705704
sdlc partner 4000.0400.0001 01
sdlc saps 01 08 04
sdlc line-speed 64000
sdlc dlsw 1
!
interface BRI0
no ip address
shutdown
!
no ip classless
ip route 10.0.0.0 255.0.0.0 Ethernet0
!
!
!
