tftp - bad checksum error? can't transfer file

Anton Shterenlikht mexas at
Thu Jul 7 22:44:37 UTC 2011

I'm trying to troubleshoot tftpd(8).

% grep boot /etc/inetd.conf
tftp   dgram udp  wait root /usr/libexec/tftpd  tftpd -dd -l -s /tftpboot
tftp   dgram udp  wait root /usr/libexec/tftpd  tftpd -dd -l -s /tftpboot
bootps dgram udp  wait root /usr/libexec/bootpd bootpd -d4 -t0 /etc/bootptab

I'm trying to boot another node via bootp/tftp.

I'm monitoring what's going on with tcpdump -vv.

bootpd starts fine, and seems to read /etc/bootptab

But after that nothing happens, and after a few minutes
I get on the console of the host which I want to boot:

> bootp()/bsd.rd.IP32
Unable to execute bootp()/bsd.rd.IP32:  invalid argument

Does this tcpdump fragment help to understand where
the problem is: > buzi.tftp: [no cksum]  25 RRQ "/bsd.rd.IP32" octet (
23:25:21.024160 IP (tos 0x0, ttl 64, id 56, offset 0, flags [none], proto UDP (1
7), length 30, bad cksum 0 (->293a)!)
    buzi.19330 > [udp sum ok] UDP, length 2
23:25:51.013759 IP (tos 0x0, ttl 255, id 256, offset 0, flags [none], proto UDP
(17), length 53)

I'm happy to provide more detailed information
on the settings I use and a longer tcpdump output,
if this helps.

Many thanks

Anton Shterenlikht
Room 2.6, Queen's Building
Mech Eng Dept
Bristol University
University Walk, Bristol BS8 1TR, UK
Tel: +44 (0)117 331 5944
Fax: +44 (0)117 929 4423

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