I'm trying to set a up a new service on a server that is running apache, however it seems like incoming traffic on that specific port is blocked, although I do not understand why. On the first server, I run netcat in listening mode on any port:
nc -l 29392
on my computer I run
nc A.B.C.D 29392
and send some text. Nothing shows up on the server. I using tcpdump to see any incoming traffic from my computer on the server, but nothing showed up. When I used tcpdump on my computer to see the outgoing data, I get the following:
tcpdump: data link type PKTAP
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on pktap, link-type PKTAP (Packet Tap), capture size 65535 bytes
16:39:16.623882 IP 192.168.0.14.56549 > A.B.C.D.29392: Flags [S], seq 1766083571, win 65535, options [mss 1460,nop,wscale 5,nop,nop,TS val 966146053 ecr 0,sackOK,eol], length 0
16:39:17.626710 IP 192.168.0.14.56549 > A.B.C.D.29392: Flags [S], seq 1766083571, win 65535, options [mss 1460,nop,wscale 5,nop,nop,TS val 966147053 ecr 0,sackOK,eol], length 0
16:39:18.627732 IP 192.168.0.14.56549 > A.B.C.D.29392: Flags [S], seq 1766083571, win 65535, options [mss 1460,nop,wscale 5,nop,nop,TS val 966148053 ecr 0,sackOK,eol], length 0
16:39:19.629946 IP 192.168.0.14.56549 > A.B.C.D.29392: Flags [S], seq 1766083571, win 65535, options [mss 1460,nop,wscale 5,nop,nop,TS val 966149053 ecr 0,sackOK,eol], length 0
16:39:20.633474 IP 192.168.0.14.56549 > A.B.C.D.29392: Flags [S], seq 1766083571, win 65535, options [mss 1460,nop,wscale 5,nop,nop,TS val 966150053 ecr 0,sackOK,eol], length 0
16:39:21.634604 IP 192.168.0.14.56549 > A.B.C.D.29392: Flags [S], seq 1766083571, win 65535, options [mss 1460,nop,wscale 5,nop,nop,TS val 966151053 ecr 0,sackOK,eol], length 0
16:39:23.640121 IP 192.168.0.14.56549 > A.B.C.D.29392: Flags [S], seq 1766083571, win 65535, options [mss 1460,nop,wscale 5,nop,nop,TS val 966153053 ecr 0,sackOK,eol], length 0
16:39:27.642574 IP 192.168.0.14.56549 > A.B.C.D.29392: Flags [S], seq 1766083571, win 65535, options [mss 1460,sackOK,eol], length 0
16:39:35.674330 IP 192.168.0.14.56549 > A.B.C.D.29392: Flags [S], seq 1766083571, win 65535, options [mss 1460,sackOK,eol], length 0
^C
9 packets captured
303 packets received by filter
0 packets dropped by kernel
But I'm unsure if there is anything interesting in there.
My computer is allowed to connect to other ports on that computer. IP-tables looks like this:
Chain INPUT (policy ACCEPT)
target prot opt source destination
fail2ban-apache-ardguest tcp -- 0.0.0.0/0 0.0.0.0/0 multiport dports 80,443
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
Chain fail2ban-apache-ardguest (1 references)
target prot opt source destination
DROP all -- X.Y.Z.V 0.0.0.0/0
RETURN all -- 0.0.0.0/0 0.0.0.0/0
The fail2ban-apache-ardguest-chain should not be related. hosts.deny is empty. What am I missing? The server is running Ubuntu 10.04.4 LTS.
