Hi Group My 2501 has a strange problem : the AUI is connected to a laptop computer which has a 10/100 pcmcia adapter. the ethernet port on 2501 is configured as follow : ip address 10.10.10.10 255.255.255.0 no keepalive the laptop is configured as 10.10.10.11/255.255.255.0 the link light on the transceive and laptop are both up and the 2501 can ping itself but not laptop,2501 is sending message like this ----when debug ethernet is on. ANCE-5-LOSTCARR: Unit 0, lost carrier. Transceiver problem? %LANCE-5-LOSTCARR: Unit 0, lost carrier. Transceiver problem? the IOS is 10.3 ,yes it's a little bit old ,but why the ethernet does not work. when i turn debug ip packet on ,the debug message is like this ---when ping the laptop Router#ping 10.10.10.11 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.10.10.11, timeout is 2 seconds: IP: s=10.10.10.10 (local), d=10.10.10.11 (Ethernet0), len 100, sending %LANCE-5-LOSTCARR: Unit 0, lost carrier. Transceiver problem? IP: s=10.10.10.10 (local), d=10.10.10.11 (Ethernet0), len 100, encapsulation failed. IP: s=10.10.10.10 (local), d=10.10.10.11 (Ethernet0), len 100, sending IP: s=10.10.10.10 (local), d=10.10.10.11 (Ethernet0), len 100, encapsulation failed. the default arp type on 2501 is ARPA----I wonder what that has got to do with the 'failed encapsulation' when pinging Do you think it is a hardware problem of the ethernet port on 2501 or AUI?? Thanks for your reply ___________________________________ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]