[syslinux] tftpd: read(ack): Connection refused

[Kosolapov Dmitry]

Luciano Miguel Ferreira Rocha wrote:
> On Thu, Mar 30, 2006 at 05:55:55AM +1100, Kosolapov Dmitry wrote:
>> Luciano Miguel Ferreira Rocha wrote:
>>> On Thu, Mar 30, 2006 at 04:42:38AM +1100, Kosolapov Dmitry wrote:
>>>> Luciano Miguel Ferreira Rocha wrote:
>>>>> On Thu, Mar 30, 2006 at 03:53:35AM +1100, Kosolapov Dmitry wrote:
>>>>>> I've checked from the 4-th subnet. No changes. TFTPD refuses remote 
>>>>>> connctions (ack requests). Please help me.
>>>>> Run /etc/init.d/iptables stop and try again.
>>>>>
>>>>> If that fixes it, you need to allow tftp traffic in your firewall. If it
>>>>> doesn't, try fetching the file via a tftp client directly on the server
>>>>> (tftp localhost) and on a machine on the same subnet.
>>>>>
>>>>>
>>>> That didn't help to it. I've tried to download the file within subnet 
>>>> server being in. Remote connections are refused. But at the server I can 
>>>> download files from /tftpboot (both 127.0.0.1 and 192.168.4.110 (my 
>>>> server's etch0 interface)).
>>> Did you run: /etc/init.d/iptables stop
>>>
>>> I suspect it's firewall related.
>>>
>> Yes, "service iptables stop" was done.
> 
> Next step:
> run
>    tcpdump -n -i eth0 -vvv port tftp
>    strace -f -p `pidof in.tftpd || pidof xinetd`
> 
> log the output from those commands while requesting the file from
> another server.
> 
> The problem could be in your gateway.
> 

The outputs while transfer attempts:
1. tcpdump -n -i eth0 -vvv port tftp

10 times message:
06:55:28.350404 IP (tos 0x0, ttl 127, id 29260, offset 0, flags [none], 
proto 17, length: 50) 80.92.161.1.3033 > 192.168.4.110.tftp: [udp sum 
ok]  22 RRQ "pxelinux.0" netascii


And at the end:

06:55:36.351908 IP (tos 0x0, ttl 127, id 29270, offset 0, flags [none], 
proto 17, length: 51) 80.92.161.1.3033 > 192.168.4.110.tftp: [udp sum 
ok]  23 ERROR EUNDEF timeout on receive"

2. strace -f -p 2119 //2119 - pid of xinetd (in.tftpd is running over 
super-server)
Process 2119 attached - interrupt to quit
select(6, [3], NULL, NULL, NULL)
And no messages while transfering.