Ubuntu Server Firewall not opening port

Wnt2bsleepin · 11-03-2013, 01:40 AM

I am trying to open port 25 using ufw, and but the port remains closed. I am able to telnet to the Postfix server locally, but cannot do it from my computer. I also ran a scan and port 25 did not show up as an active port.

Code:

PORT    STATE SERVICE
22/tcp  open  ssh
80/tcp  open  http
443/tcp open  https

Any help is much appreciated.

ericson007 · 11-04-2013, 07:30 PM

So what command did you try using? Please explain your steps otherwise it takes longer to resolve issues, because right now it would be a stab in te dark with a typical response like read the manual and run the command properly checking for spelling mistakes

Code:

sudo ufw allow 25

Wnt2bsleepin · 11-07-2013, 09:16 PM

I added it using

Code:

sudo ufw allow 25

It verifies that the rules are already in there.

Code:

Skipping adding existing rule
Skipping adding existing rule (v6)

Here is the output of

Code:

iptables -L

Code:

Chain INPUT (policy DROP)
target     prot opt source               destination
ufw-before-logging-input  all  --  anywhere             anywhere
ufw-before-input  all  --  anywhere             anywhere
ufw-after-input  all  --  anywhere             anywhere
ufw-after-logging-input  all  --  anywhere             anywhere
ufw-reject-input  all  --  anywhere             anywhere
ufw-track-input  all  --  anywhere             anywhere

Chain FORWARD (policy DROP)
target     prot opt source               destination
ufw-before-logging-forward  all  --  anywhere             anywhere
ufw-before-forward  all  --  anywhere             anywhere
ufw-after-forward  all  --  anywhere             anywhere
ufw-after-logging-forward  all  --  anywhere             anywhere
ufw-reject-forward  all  --  anywhere             anywhere

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination
ufw-before-logging-output  all  --  anywhere             anywhere
ufw-before-output  all  --  anywhere             anywhere
ufw-after-output  all  --  anywhere             anywhere
ufw-after-logging-output  all  --  anywhere             anywhere
ufw-reject-output  all  --  anywhere             anywhere
ufw-track-output  all  --  anywhere             anywhere

Chain ufw-after-forward (1 references)
target     prot opt source               destination

Chain ufw-after-input (1 references)
target     prot opt source               destination
ufw-skip-to-policy-input  udp  --  anywhere             anywhere             udp dpt:netbios-ns
ufw-skip-to-policy-input  udp  --  anywhere             anywhere             udp dpt:netbios-dgm
ufw-skip-to-policy-input  tcp  --  anywhere             anywhere             tcp dpt:netbios-ssn
ufw-skip-to-policy-input  tcp  --  anywhere             anywhere             tcp dpt:microsoft-ds
ufw-skip-to-policy-input  udp  --  anywhere             anywhere             udp dpt:bootps
ufw-skip-to-policy-input  udp  --  anywhere             anywhere             udp dpt:bootpc
ufw-skip-to-policy-input  all  --  anywhere             anywhere             ADDRTYPE match dst-type BROADCAST

Chain ufw-after-logging-forward (1 references)
target     prot opt source               destination
LOG        all  --  anywhere             anywhere             limit: avg 3/min burst 10 LOG level warning prefix "[UFW BLOCK] "

Chain ufw-after-logging-input (1 references)
target     prot opt source               destination
LOG        all  --  anywhere             anywhere             limit: avg 3/min burst 10 LOG level warning prefix "[UFW BLOCK] "

Chain ufw-after-logging-output (1 references)
target     prot opt source               destination

Chain ufw-after-output (1 references)
target     prot opt source               destination

Chain ufw-before-forward (1 references)
target     prot opt source               destination
ufw-user-forward  all  --  anywhere             anywhere

Chain ufw-before-input (1 references)
target     prot opt source               destination
ACCEPT     all  --  anywhere             anywhere
ACCEPT     all  --  anywhere             anywhere             state RELATED,ESTABLISHED
ufw-logging-deny  all  --  anywhere             anywhere             state INVALID
DROP       all  --  anywhere             anywhere             state INVALID
ACCEPT     icmp --  anywhere             anywhere             icmp destination-unreachable
ACCEPT     icmp --  anywhere             anywhere             icmp source-quench
ACCEPT     icmp --  anywhere             anywhere             icmp time-exceeded
ACCEPT     icmp --  anywhere             anywhere             icmp parameter-problem
ACCEPT     icmp --  anywhere             anywhere             icmp echo-request
ACCEPT     udp  --  anywhere             anywhere             udp spt:bootps dpt:bootpc
ufw-not-local  all  --  anywhere             anywhere
ACCEPT     udp  --  anywhere             224.0.0.251          udp dpt:mdns
ACCEPT     udp  --  anywhere             239.255.255.250      udp dpt:1900
ufw-user-input  all  --  anywhere             anywhere

Chain ufw-before-logging-forward (1 references)
target     prot opt source               destination

Chain ufw-before-logging-input (1 references)
target     prot opt source               destination

Chain ufw-before-logging-output (1 references)
target     prot opt source               destination

Chain ufw-before-output (1 references)
target     prot opt source               destination
ACCEPT     all  --  anywhere             anywhere
ACCEPT     all  --  anywhere             anywhere             state RELATED,ESTABLISHED
ufw-user-output  all  --  anywhere             anywhere

Chain ufw-logging-allow (0 references)
target     prot opt source               destination
LOG        all  --  anywhere             anywhere             limit: avg 3/min burst 10 LOG level warning prefix "[UFW ALLOW] "

Chain ufw-logging-deny (2 references)
target     prot opt source               destination
RETURN     all  --  anywhere             anywhere             state INVALID limit: avg 3/min burst 10
LOG        all  --  anywhere             anywhere             limit: avg 3/min burst 10 LOG level warning prefix "[UFW BLOCK] "

Chain ufw-not-local (1 references)
target     prot opt source               destination
RETURN     all  --  anywhere             anywhere             ADDRTYPE match dst-type LOCAL
RETURN     all  --  anywhere             anywhere             ADDRTYPE match dst-type MULTICAST
RETURN     all  --  anywhere             anywhere             ADDRTYPE match dst-type BROADCAST
ufw-logging-deny  all  --  anywhere             anywhere             limit: avg 3/min burst 10
DROP       all  --  anywhere             anywhere

Chain ufw-reject-forward (1 references)
target     prot opt source               destination

Chain ufw-reject-input (1 references)
target     prot opt source               destination

Chain ufw-reject-output (1 references)
target     prot opt source               destination

Chain ufw-skip-to-policy-forward (0 references)
target     prot opt source               destination
DROP       all  --  anywhere             anywhere

Chain ufw-skip-to-policy-input (7 references)
target     prot opt source               destination
DROP       all  --  anywhere             anywhere

Chain ufw-skip-to-policy-output (0 references)
target     prot opt source               destination
ACCEPT     all  --  anywhere             anywhere

Chain ufw-track-input (1 references)
target     prot opt source               destination

Chain ufw-track-output (1 references)
target     prot opt source               destination
ACCEPT     tcp  --  anywhere             anywhere             state NEW
ACCEPT     udp  --  anywhere             anywhere             state NEW

Chain ufw-user-forward (1 references)
target     prot opt source               destination

Chain ufw-user-input (1 references)
target     prot opt source               destination
ACCEPT     tcp  --  anywhere             anywhere             tcp dpt:smtp
ACCEPT     udp  --  anywhere             anywhere             udp dpt:25
ACCEPT     tcp  --  anywhere             anywhere             tcp dpt:ssh
ACCEPT     udp  --  anywhere             anywhere             udp dpt:ssh
ACCEPT     tcp  --  anywhere             anywhere             tcp dpt:http
ACCEPT     udp  --  anywhere             anywhere             udp dpt:http
ACCEPT     tcp  --  anywhere             anywhere             tcp dpt:https
ACCEPT     udp  --  anywhere             anywhere             udp dpt:https
ACCEPT     tcp  --  anywhere             anywhere             tcp dpt:64738
ACCEPT     udp  --  anywhere             anywhere             udp dpt:64738

Chain ufw-user-limit (0 references)
target     prot opt source               destination
LOG        all  --  anywhere             anywhere             limit: avg 3/min burst 5 LOG level warning prefix "[UFW LIMIT BLOCK] "
REJECT     all  --  anywhere             anywhere             reject-with icmp-port-unreachable

Chain ufw-user-limit-accept (0 references)
target     prot opt source               destination
ACCEPT     all  --  anywhere             anywhere

Chain ufw-user-logging-forward (0 references)
target     prot opt source               destination

Chain ufw-user-logging-input (0 references)
target     prot opt source               destination

Chain ufw-user-logging-output (0 references)
target     prot opt source               destination

Chain ufw-user-output (1 references)
target     prot opt source               destination

ericson007 · 11-08-2013, 02:47 AM

Can you see the rule mentioning the port specifically in the iptables configuration file?

ericson007 · 11-08-2013, 02:53 AM

Maybe also just try to ensure that traffic can actually get out.

Code:

sudo ufw allow out 25

Then try

Code:

telnet ip.add.of.server 25

descendant_command · 11-08-2013, 02:55 AM

Is postfix listening on that interface?