[ECOS] telnet in redboot

Cho JinJe winjjcho@hotmail.com
Fri Jan 24 03:50:00 GMT 2003


I have already accessed target on serial port.

below is tcpdump message:

tcpdump -v
tcpdump: listening on eth0
11:22:36.376854 arp who-has 192.168.1.14 tell 192.168.1.10
11:22:36.383097 arp reply 192.168.1.14 is-at 91:5:c6:1:56:40
11:22:36.383134 192.168.1.10.32771 > 192.168.1.14.9000: S [tcp sum ok] 
1178106054:1178106054(0) win 5840 <mss 1460,sackOK,timestamp 1683156 
0,nop,wscale 0> (DF) [tos 0x10]  (ttl 64, id 54802, len 60)
11:22:36.385255 192.168.1.14.9000 > 192.168.1.10.32771: S [tcp sum ok] 
0:0(0) ack 1178106055 win 1472 <mss 1472> (ttl 64, id 1, len 44)
11:22:36.385333 192.168.1.10.32771 > 192.168.1.14.9000: . [tcp sum ok] ack 
1 win 5840 (DF) [tos 0x10]  (ttl 64, id 54803, len 40)
11:22:36.388774 192.168.1.14.9000 > 192.168.1.10.32771: P [bad tcp cksum 
20!] 1:10(9) ack 1 win 1472 (ttl 64, id 2, len 49)
11:22:37.425774 192.168.1.14.9000 > 192.168.1.10.32771: P [bad tcp cksum 
20!] 1:10(9) ack 1 win 1472 (ttl 64, id 3, len 49)
11:22:38.462727 192.168.1.14.9000 > 192.168.1.10.32771: P [bad tcp cksum 
20!] 1:10(9) ack 1 win 1472 (ttl 64, id 4, len 49)
 ....

20 packets received by filter
0 packets dropped by kernel

what does 'bad tcp cksum 20!' mean?

thanks!

jjcho


>From: Jonathan Larmour <jifl@eCosCentric.com>
>To: Cho JinJe <winjjcho@hotmail.com>
>CC: ecos-discuss@sources.redhat.com
>Subject: Re: [ECOS]  telnet in redboot
>Date: Thu, 23 Jan 2003 22:14:34 +0000
>
>Cho JinJe wrote:
> > Hi, all
> >
> > I have a question about telnet in redboot.
> > I have ported redboot to SH7709s custom board which has cs8900a 
ethernet
> > interface.
> >
> > Ping is ok(both of host and target).
> > but when I open telnet connection, I can't see 'redboot>' prompt in 
shell.
> >
> > [root@localhost root]# telnet 192.168.1.14 9000
> > Trying 192.168.1.14...
> > Connected to 192.168.1.14.
> > Escape character is '^]'.
> >                               <- there is no prompt.
>
>Have you already accessed it on another port like a serial port? This
>shouldn't make a difference as I believe telnet should work regardless,
>but it might.
>
>Other than that, I suggest running an ethernet sniffer like tcpdump on
>your host to see if the target is sending _anything_. I take it you've
>confirmed that it thinks it's working, with good MAC address and IP.
>
>Jifl
>--
>eCosCentric       http://www.eCosCentric.com/       <info@eCosCentric.com>
>--[ "You can complain because roses have thorns, or you ]--
>--[  can rejoice because thorns have roses." -Lincoln   ]-- Opinions==mine


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