[CentOS] tftpd server S not responding

Thu Apr 12 06:25:37 UTC 2018
peter.winterflood <peter.winterflood at ossi.co.uk>

have you checked that tftp is added to hosts.allow.
syslog may be reporting libwrap errors, libwrap is trcpwrappers
regards peter


On 11 April 2018 16:57:04 "Asif Iqbal" <vadud3 at gmail.com> wrote:

> On Thu, Mar 29, 2018 at 12:48 PM, Asif Iqbal <vadud3 at gmail.com> wrote:
>
> >
> >
> > On Thu, Mar 29, 2018 at 7:21 AM, Steven Tardy <sjt5atra at gmail.com> wrote:
> >
>> > A STATEFUL firewall with “ip any any” can and will still block asymmetric
>> > communications due to the firewall keeping track of state (hence tha name
>> > stateful firewall).
>> >
>> > Tcpdump on your servers /other/ NICs and you’ll see the tftp traffic
>> > leaving your server on some other NIC (probably on with the default
>> > route).
>> >
> >
> > A (192.168.1.10)
> > S (192.168.1.20)
> >
> > I do not see tftp traffic is leaving from S
> >
> > A:~$ tftp
> > (to) 192.168.1.20
> > tftp> get file
> > Transfer timed out.
> >
> > As you can see no pkt is leaving. If it were leaving S, but A were not
> > receiving then I would think firewall
> > is dropping it.
> >
> > [ S ~]$ sudo tcpdump -A -nniany host 192.168.1.10
> > tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
> > listening on any, link-type LINUX_SLL (Linux cooked), capture size 262144
> > bytes
> >
> > 16:40:08.390939 IP 192.168.1.10.35553 > 192.168.1.20.69:  16 RRQ "file"
> > netascii
> > E..,J1 at .>..n./...oAt...E..#...file.netascii...................
> > 16:40:13.391133 IP 192.168.1.10.35553 > 192.168.1.20.69:  16 RRQ "file"
> > netascii
> > E..,N. at .>..../...oAt...E..#...file.netascii...................
> > 16:40:18.391220 IP 192.168.1.10.35553 > 192.168.1.20.69:  16 RRQ "file"
> > netascii
> > E..,QK at .>..T./...oAt...E..#...file.netascii...................
> > 16:40:23.391373 IP 192.168.1.10.35553 > 192.168.1.20.69:  16 RRQ "file"
> > netascii
> > E..,T^@.>.. at ./...oAt...E..#...file.netascii...................
> > 16:40:28.391469 IP 192.168.1.10.35553 > 192.168.1.20.69:  16 RRQ "file"
> > netascii
> > E..,X. at .>..../...oAt...E..#...file.netascii...................
> >
> >
> >
> I still like some help on this
>
>
> >
> >
>> >
>> > The upstream firewall will then block the tftp response if it never saw
>> > the
>> > tftp request (due to asymmetry).
>> > _______________________________________________
>> > CentOS mailing list
>> > CentOS at centos.org
>> > https://lists.centos.org/mailman/listinfo/centos
>> >
> >
> >
> >
> >
> --
> Asif Iqbal
> PGP Key: 0xE62693C5 KeyServer: pgp.mit.edu
> A: Because it messes up the order in which people normally read text.
> Q: Why is top-posting such a bad thing?
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos


Sent with AquaMail for Android
https://www.mobisystems.com/aqua-mail