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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). The upstream firewall will then block the tftp response if it never saw the tftp

...tp 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 &g...

...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....

...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 Most likely the firewall on the system running your tftp client is blocking the traffic from the tftp server....

...ftp > > (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 "fi...