Getting timeouts on TFTP on F15 as well as F14

Frantisek Hanzlik franta at hanzlici.cz
Mon Oct 10 21:20:18 UTC 2011


Aaron Gray wrote:
...
> 
>     4) if You use firewall (iptables), You should load nf_conntrack_tftp module,
>     for tracking ephemeral ports. That means /etc/sysconfig/iptables-config should
>     contain line as:
>     ...
>     IPTABLES_MODULES="nf_conntrack_tftp"
>     ...
>     (other module is for NATting tftp connection)
> 
> 
> using localhost

loopback (lo interface) is subject to firewall rules too. And Your tcpdump
below show IP addresses 192.168.0.4 and 192.168.0.5 - they perhaps are not
at lo loopback interface?
Have You firewall active?

>  
> 
> 
>     5) /var/log/messages should contain entries as:
>     Oct 10 20:28:32 ns xinetd[1908]: START: tftp pid=5315 from=192.168.1.22
>     Oct 10 20:28:42 ns xinetd[1908]: EXIT: tftp status=0 pid=5315 duration=10(sec)
> 
> 
> Oct 10 21:09:07 gold xinetd[13402]: Exiting...
> Oct 10 21:09:12 gold xinetd[13650]: xinetd Version 2.3.14 started with libwrap loadavg
> labeled-networking options compiled in.
> Oct 10 21:09:12 gold xinetd[13650]: Started working: 1 available service

There isn't nothing about that xinetd starts tftp daemon. Mentioned
"1 available service" is tftp?
This command show only tftp:

# grep '^[[:blank:]]*disable.*no' /etc/xinetd.d/*
/etc/xinetd.d/tftp:	disable	= no

Next command display some similar at Your server?:
# netstat -a -n -p --ip|grep 69
udp        0      0 0.0.0.0:69           0.0.0.0:*      1595/xinetd

Can You post Your "/etc/xinetd.d/tftp" file?

> 
> is all I am getting in messages
> 
> Checked tfpt is the only one enabled
>  
> 
> 
> 
>     6) tcpdump on relevant interface (here eth0) should display traffic,
>     at minimal incomming packet:
>     # tcpdump -i eth0 -l -nn udp port 69
>     tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
>     listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
>     20:43:13.612200 IP 192.168.1.22.58949 > 192.168.1.254.69:  17 RRQ "b.log" netascii
> 
> 
> [root at xxxxx /]# tcpdump -i em1 -l -nn udp port 69
> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
> listening on em1, link-type EN10MB (Ethernet), capture size 65535 bytes
> 21:33:08.653033 IP 192.168.0.5.47352 > 192.168.0.4.69:  19 RRQ "vmlinuz" netascii
> 21:33:13.653306 IP 192.168.0.5.47352 > 192.168.0.4.69:  19 RRQ "vmlinuz" netascii
> 21:33:18.653565 IP 192.168.0.5.47352 > 192.168.0.4.69:  19 RRQ "vmlinuz" netascii
> 21:33:23.653963 IP 192.168.0.5.47352 > 192.168.0.4.69:  19 RRQ "vmlinuz" netascii
> 21:33:28.654212 IP 192.168.0.5.47352 > 192.168.0.4.69:  19 RRQ "vmlinuz" netascii
> ^C
> 5 packets captured
> 5 packets received by filter
> 0 packets dropped by kernel

It isn't traffic at localhost, as You wrote above, em1 is external interface.

With default timeout (900 sec=15min), You should be seing tftp running.
E.g. "ps xa|grep tftp" should display it. But there isn't line in messages
that xinetd start tftp daemon.

Most likely there is firewall or SELinux blocking incomming packets - can
You stop them?

tcpdump usualy not display something other than first packet, as next dialog
(second and next packets) run at ephemeral port.

> 
> Well thats it I am stumped tftp seem to be running but ignoring requests
> 
> Aaron


Franta


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