I have an HP Jetdirect print server that needs to be accessed over a WAN. I configured iptables to allow port 9100 through the firewall and have tailed the logs and there are no packets bouncing off. Here is the strangeness:

Text based print jobs go through fine. Print jobs that include a graphic fail!

I used tcpdump to watch the packets and it seems that I get to a certain point and then it fails. It gets to the same point every time. I can't find a thing about this on the Internet anywhere.

Please HELP!

Here is a cut and paste from tcpdump:

17:51:13.606356 192.168.1.20.52596 > xxx.yyy.zzz.100.jetdirect: . 2744:4112(1368) ack 1 win 24840 <nop,nop,timestamp 14196392 28111> (DF) (ttl 64, id 19740, len 1420)
17:51:13.606420 192.168.1.20.52596 > xxx.yyy.zzz.100.jetdirect: . 4112:5480(1368) ack 1 win 24840 <nop,nop,timestamp 14196392 28111> (DF) (ttl 64, id 19741, len 1420)
17:51:13.749959 xxx.yyy.zzz.100.jetdirect > 192.168.1.20.52596: . [tcp sum ok] 1:1(0) ack 5480 win 64240 <nop,nop,timestamp 28111 14196385> (ttl 46, id 1456, len 52)
17:51:13.750356 192.168.1.20.52596 > xxx.yyy.zzz.100.jetdirect: . 5480:6848(1368) ack 1 win 24840 <nop,nop,timestamp 14196406 28111> (DF) (ttl 64, id 19743, len 1420)
17:51:13.750432 192.168.1.20.52596 > xxx.yyy.zzz.100.jetdirect: . 6848:8216(1368) ack 1 win 24840 <nop,nop,timestamp 14196406 28111> (DF) (ttl 64, id 19744, len 1420)
17:51:13.750479 192.168.1.20.52596 > xxx.yyy.zzz.100.jetdirect: . 8216:9584(1368) ack 1 win 24840 <nop,nop,timestamp 14196406 28111> (DF) (ttl 64, id 19745, len 1420)
17:51:13.750576 192.168.1.20.52596 > xxx.yyy.zzz.100.jetdirect: . 9584:10952(1368) ack 1 win 24840 <nop,nop,timestamp 14196406 28111> (DF) (ttl 64, id 19746, len 1420)
17:51:13.893811 xxx.yyy.zzz.100.jetdirect > 192.168.1.20.52596: . [tcp sum ok] 1:1(0) ack 5480 win 64240 <nop,nop,timestamp 28112 14196385> (ttl 46, id 1458, len 52)
17:51:13.902202 xxx.yyy.zzz.100.jetdirect > 192.168.1.20.52596: . [tcp sum ok] 1:1(0) ack 5480 win 64240 <nop,nop,timestamp 28112 14196385> (ttl 46, id 1460, len 52)
17:51:13.909932 xxx.yyy.zzz.100.jetdirect > 192.168.1.20.52596: . [tcp sum ok] 1:1(0) ack 5480 win 64240 <nop,nop,timestamp 28112 14196385> (ttl 46, id 1462, len 52)
17:51:13.910184 192.168.1.20.52596 > xxx.yyy.zzz.100.jetdirect: . 5480:6848(1368) ack 1 win 24840 <nop,nop,timestamp 14196422 28112> (DF) (ttl 64, id 19747, len 1420)
17:51:14.901608 192.168.1.20.52596 > xxx.yyy.zzz.100.jetdirect: . 5480:6848(1368) ack 1 win 24840 <nop,nop,timestamp 14196522 28112> (DF) (ttl 64, id 19753, len 1420)
17:51:15.901604 192.168.1.20.52596 > xxx.yyy.zzz.100.jetdirect: . 5480:6848(1368) ack 1 win 24840 <nop,nop,timestamp 14196622 28112> (DF) (ttl 64, id 19762, len 1420)
17:51:17.621854 192.168.1.20.52596 > xxx.yyy.zzz.100.jetdirect: . 5480:6848(1368) ack 1 win 24840 <nop,nop,timestamp 14196794 28112> (DF) (ttl 64, id 19770, len 1420)


Thank you in advance!

I configured iptables to allow port 9100 through the firewall and have tailed the logs and there are no packets bouncing off. Here is the strangeness: Text based print jobs go through fine. Print jobs that include a graphic fail!
What I would do is check with whatever hpj.* tools you got what the status of the printer is during a run, just to make sure it's not that. Then I would add LOG target rules before block rules for the printer. That way you see what get's dropped and what port(range) you need to open.

Well... It appears that it was a network card problem. There was a Gigabit NIC in the firewall using the e1000 driver and we switched to a 100/Mb using the e100 driver and the problem went away. It could be the e1000 driver, firmware on the NIC, the network switch, the Cisco router...etc.. etc... only going back to troubleshoot will give me a definite answer, but unfortunately, the machine is now in production so it looks like it will remain a mystery.