CentOS 6.4: tftpd Connection refused

fjkum · 03-03-2014, 12:41 AM

Hi,

I am facing a problem getting the tftpd to work.

Here is my hardware setup:
(1) Two NICs (both detected during boot)
(2) CentOS 6.4 32-bit
(3) tftpd-server installed (yum install tftpd-server)
(4) tftp client installed (yum install tftp)

First NIC is connected to corporate network (DHCP). the second NIC is used for the tftp server (Static IP).

Here are my things that I have done so far:
(1) Edited /etc/selinux/config and disable the SELINUX. (Rebooted after making the change)
(2) Edited /etc/xinetd.d/tftp to include '-vvv' in the server_args to show more messages in the /var/log/messages.
(3) Restarted xinetd. (service xinetd restart)
(4) Disabled Firewall.
(5) Tested locally for tftp file transfer and it works.
(6) Connect the tftp client device.
(7) Getting the following message in /var/log/messages:

Mar 3 21:40:14 localhost in.tftpd[2867]: RRQ from 192.168.3.1 filename bootfile
Mar 3 21:40:14 localhost in.tftpd[2867]: tftpd: read(ack): Connection refused

So, I have ran out of options to try. Anyone can shed some light?

TIA.

custangro · 03-03-2014, 05:52 PM

What does your /etc/xinetd.d/tftp file look like (please use code tags) and what are the permissions on the filesystem?

--C

smallpond · 03-03-2014, 06:01 PM

Quote:

Originally Posted by fjkum

Hi,

I am facing a problem getting the tftpd to work.

Here is my hardware setup:
(1) Two NICs (both detected during boot)
(2) CentOS 6.4 32-bit
(3) tftpd-server installed (yum install tftpd-server)
(4) tftp client installed (yum install tftp)

First NIC is connected to corporate network (DHCP). the second NIC is used for the tftp server (Static IP).

I'm not sure I understand what you are saying. Are you mixing together the description of your server and your client, or are you trying to run the tftp server and client on the same system?

Assuming that they are separate, does the client have a single ethernet port which connects to the server's static IP NIC and is it on the same network segment (no NAT or routers in between)?

Assuming it is on the same segment, are routes correct in the server? Show the route table.

fjkum · 03-03-2014, 09:24 PM

Quote:

Originally Posted by smallpond

I'm not sure I understand what you are saying. Are you mixing together the description of your server and your client, or are you trying to run the tftp server and client on the same system?

Assuming that they are separate, does the client have a single ethernet port which connects to the server's static IP NIC and is it on the same network segment (no NAT or routers in between)?

Assuming it is on the same segment, are routes correct in the server? Show the route table.

Hi,

The client and the server are separate. And yes, I can ping the client IP from Server side and the client is using only one ethernet port. So this means they are both falls in the same segment.

The server side has two physical NIC cards. The client is connected directly to the second NIC (eth3).

Code:

[root@localhost ~]# route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.0.0     *               255.255.252.0   U     1      0        0 eth3
10.128.112.0    *               255.255.248.0   U     1      0        0 eth0
default         10.128.112.1    0.0.0.0         UG    0      0        0 eth0
[root@localhost ~]#

---------- Post added 03-03-14 at 22:24 ----------

Quote:

Originally Posted by custangro

What does your /etc/xinetd.d/tftp file look like (please use code tags) and what are the permissions on the filesystem?

--C

Code:

[root@localhost ~]# cat /etc/xinetd.d/tftp
# default: off
# description: The tftp server serves files using the trivial file transfer \
#	protocol.  The tftp protocol is often used to boot diskless \
#	workstations, download configuration files to network-aware printers, \
#	and to start the installation process for some operating systems.
service tftp
{
	disable	= no
	socket_type		= dgram
	protocol		= udp
	#port                    = 6969
	wait			= yes
	user			= root
	server			= /usr/sbin/in.tftpd
	server_args		= -vv -s /var/lib/tftpboot
	per_source		= 11
	cps			= 100 2
	flags			= IPv4
}

smallpond · 03-04-2014, 09:56 AM

I guess use tcpdump on interface eth3 on server and see where the protocol breaks down.

custangro · 03-04-2014, 12:14 PM

What does...

Code:

ls -lAFhd /var/lib/tftpboot
ls -lAFh /var/lib/tftpboot

Show?

fjkum · 03-05-2014, 12:08 AM

Quote:

Originally Posted by custangro

What does...

Code:

ls -lAFhd /var/lib/tftpboot
ls -lAFh /var/lib/tftpboot

Show?

Code:

[root@localhost ~]# ls -lAFhd /var/lib/tftpboot
drwxrwxrwx. 4 root root 4.0K Sep 23  2011 /var/lib/tftpboot/

[root@localhost /]# ls -lAFh /var/lib/tftpboot/
total 116K
-rwxrwxrwx. 1 nobody nobody 113K Mar  3 18:53 boot_fw*

fjkum · 03-05-2014, 12:09 AM

Quote:

Originally Posted by smallpond

I guess use tcpdump on interface eth3 on server and see where the protocol breaks down.

Code:

Output from 'tcpdump -i eth3 -vvnn':
[root@localhost ~]# tcpdump -i eth3 -vvnn
tcpdump: listening on eth3, link-type EN10MB (Ethernet), capture size 65535 bytes
18:57:18.751902 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.3.1 tell 192.168.3.1, length 46
18:57:20.804436 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.251 tell 192.168.3.1, length 46
18:57:20.804449 ARP, Ethernet (len 6), IPv4 (len 4), Reply 192.168.1.251 is-at 00:02:b3:4b:3b:d7, length 28
18:57:20.804685 IP (tos 0x0, ttl 255, id 0, offset 0, flags [none], proto UDP (17), length 544)
    192.168.3.1.7001 > 192.168.1.251.6969: [udp sum ok]  rx type 0 cid 74616c6f call# 1851744879 seq 1869873263 ser 1668572532 (516)
18:57:20.805801 IP (tos 0x0, ttl 64, id 30813, offset 0, flags [DF], proto UDP (17), length 544)
    192.168.1.251.6988 > 192.168.3.1.7001: [udp sum ok]  rx type 192 cid 481fd703 call# -2147287004 seq -338870208 ser 1210457638 <more-pckts> (516)
18:57:20.806088 IP (tos 0x0, ttl 255, id 1, offset 0, flags [none], proto ICMP (1), length 56)
    192.168.3.1 > 192.168.1.251: ICMP 192.168.3.1 udp port 7001 unreachable, length 36
    IP (tos 0x0, ttl 64, id 30813, offset 0, flags [DF], proto UDP (17), length 544)
    192.168.1.251.6988 > 192.168.3.1.7001:  [|rx] (516)