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I have an Ubuntu 12.10 machine on my LAN to which all ssh connections time out. Let's call it 'F' (for fail!)

Two other machines 'A' and 'B' on the same LAN can connect to each other. I can also ssh from F to A. So I don't believe there is a network config issue. The problem seems to be confined to machine F.

Following various other forums answers, I've verified and tried the following.

Verify sshd is running and listening on port 22:

F$ ps -A | grep sshd
853 ?        00:00:00 sshd

F$ sudo ss -lnp | grep sshd
LISTEN     0      128                      :::22                      :::*      users:(("sshd",4244,4))
LISTEN     0      128                       *:22                       *:*      users:(("sshd",4244,3))

F$ sudo lsof -i | grep ssh
sshd      4244    root    3u  IPv4  53321      0t0  TCP *:ssh (LISTEN)
sshd      4244    root    4u  IPv6  53323      0t0  TCP *:ssh (LISTEN)
ssh       5244 michael    3u  IPv4  82208      0t0  TCP localhost:40209->cubebot:ssh (ESTABLISHED)
sshd      5245    root    3u  IPv4  83301      0t0  TCP cubebot:ssh->localhost:40209 (ESTABLISHED)
sshd      5362 michael    3u  IPv4  83301      0t0  TCP cubebot:ssh->localhost:40209 (ESTABLISHED)

F$ netstat -nat | grep 22
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN     
tcp        0      0 192.168.1.28:41782      74.125.225.209:443      ESTABLISHED
tcp        0      0 192.168.1.28:47576      74.125.142.125:5222     ESTABLISHED
tcp        0      0 192.168.1.28:54925      91.189.89.122:443       ESTABLISHED
tcp        0      0 192.168.1.28:54762      74.125.225.167:443      ESTABLISHED
tcp        0      0 192.168.1.28:48473      74.125.225.181:443      ESTABLISHED
tcp        0      0 192.168.1.28:36177      74.125.225.198:443      ESTABLISHED
tcp6       0      0 :::22                   :::*                    LISTEN     

Try telnet:

A$ telnet F 22
Trying 192.168.1.28...
telnet: Unable to connect to remote host: Connection timed out

The same thing happens with ssh. The IP address for F is correct:

F$ ifconfig
wlan1     Link encap:Ethernet  HWaddr 00:1a:70:3b:58:2e  
          inet addr:192.168.1.28  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::21a:70ff:fe3b:582e/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:22070 errors:0 dropped:0 overruns:0 frame:0
          TX packets:15344 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:12137460 (12.1 MB)  TX bytes:2564022 (2.5 MB)

The hosts look correct:

F$ cat /etc/hosts
127.0.0.1   localhost
127.0.1.1   cubebot

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

Where cubebot is machine 'F' and the hostname is correct:

$ cat /etc/hostname
cubebot

Using localhost and hostname on machine F both work:

F$ ssh localhost
Welcome to Ubuntu 12.10 (GNU/Linux 3.5.0-31-generic x86_64)

F$ ssh cubebot
Welcome to Ubuntu 12.10 (GNU/Linux 3.5.0-31-generic x86_64)

Output of sudo iptables -L -nv:

Chain INPUT (policy DROP 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
   65  8910 ACCEPT     tcp  --  *      *       127.0.1.1            0.0.0.0/0            tcpflags:! 0x17/0x02
 4468  479K ACCEPT     udp  --  *      *       127.0.1.1            0.0.0.0/0           
 4850  337K ACCEPT     all  --  lo     *       0.0.0.0/0            0.0.0.0/0           
    4   336 ACCEPT     icmp --  *      *       0.0.0.0/0            0.0.0.0/0            limit: avg 10/sec burst 5
 2139  384K DROP       all  --  wlan1  *       0.0.0.0/0            255.255.255.255     
 1898  327K DROP       all  --  *      *       0.0.0.0/0            192.168.1.255       
    0     0 DROP       all  --  *      *       224.0.0.0/8          0.0.0.0/0           
    0     0 DROP       all  --  *      *       0.0.0.0/0            224.0.0.0/8         
    0     0 DROP       all  --  *      *       255.255.255.255      0.0.0.0/0           
    0     0 DROP       all  --  *      *       0.0.0.0/0            0.0.0.0             
    1    40 DROP       all  --  *      *       0.0.0.0/0            0.0.0.0/0            state INVALID
0     0 LSI        all  -f  *      *       0.0.0.0/0            0.0.0.0/0            limit: avg 10/min burst 5
 674K  975M INBOUND    all  --  wlan1  *       0.0.0.0/0            0.0.0.0/0           
    0     0 LOG_FILTER  all  --  *      *       0.0.0.0/0            0.0.0.0/0           
    0     0 LOG        all  --  *      *       0.0.0.0/0            0.0.0.0/0            LOG flags 0 level 6 prefix "Unknown Input"

Chain FORWARD (policy DROP 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 ACCEPT     icmp --  *      *       0.0.0.0/0            0.0.0.0/0            limit: avg 10/sec burst 5
    0     0 LOG_FILTER  all  --  *      *       0.0.0.0/0            0.0.0.0/0           
    0     0 LOG        all  --  *      *       0.0.0.0/0            0.0.0.0/0            LOG flags 0 level 6 prefix "Unknown Forward"

Chain OUTPUT (policy DROP 524 packets, 88964 bytes)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 ACCEPT     tcp  --  *      *       192.168.1.28         127.0.1.1            tcp dpt:53
    0     0 ACCEPT     udp  --  *      *       192.168.1.28         127.0.1.1            udp dpt:53
 9383  825K ACCEPT     all  --  *      lo      0.0.0.0/0            0.0.0.0/0           
    0     0 DROP       all  --  *      *       224.0.0.0/8          0.0.0.0/0           
    0     0 DROP       all  --  *      *       0.0.0.0/0            224.0.0.0/8         
    0     0 DROP       all  --  *      *       255.255.255.255      0.0.0.0/0           
    0     0 DROP       all  --  *      *       0.0.0.0/0            0.0.0.0             
   49  3372 DROP       all  --  *      *       0.0.0.0/0            0.0.0.0/0            state INVALID
 383K   20M OUTBOUND   all  --  *      wlan1   0.0.0.0/0            0.0.0.0/0           
  524 88964 LOG_FILTER  all  --  *      *       0.0.0.0/0            0.0.0.0/0           
  524 88964 LOG        all  --  *      *       0.0.0.0/0            0.0.0.0/0            LOG flags 0 level 6 prefix "Unknown Output"

Chain INBOUND (1 references)
 pkts bytes target     prot opt in     out     source               destination         
 669K  974M ACCEPT     tcp  --  *      *       0.0.0.0/0            0.0.0.0/0            state RELATED,ESTABLISHED
 4883  511K ACCEPT     udp  --  *      *       0.0.0.0/0            0.0.0.0/0            state RELATED,ESTABLISHED
    0     0 ACCEPT     all  --  *      *       192.168.1.14         0.0.0.0/0           
   76  5013 LSI        all  --  *      *       0.0.0.0/0            0.0.0.0/0           

Chain LOG_FILTER (5 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain LSI (2 references)
 pkts bytes target     prot opt in     out     source               destination         
   76  5013 LOG_FILTER  all  --  *      *       0.0.0.0/0            0.0.0.0/0           
   44  2640 LOG        tcp  --  *      *       0.0.0.0/0            0.0.0.0/0            tcpflags: 0x17/0x02 limit: avg 1/sec burst 5 LOG flags 0 level 6 prefix "Inbound "
   44  2640 DROP       tcp  --  *      *       0.0.0.0/0            0.0.0.0/0            tcpflags: 0x17/0x02
    0     0 LOG        tcp  --  *      *       0.0.0.0/0            0.0.0.0/0            tcpflags: 0x17/0x04 limit: avg 1/sec burst 5 LOG flags 0 level 6 prefix "Inbound "
    0     0 DROP       tcp  --  *      *       0.0.0.0/0            0.0.0.0/0            tcpflags: 0x17/0x04
    0     0 LOG        icmp --  *      *       0.0.0.0/0            0.0.0.0/0            icmptype 8 limit: avg 1/sec burst 5 LOG flags 0 level 6 prefix "Inbound "
    0     0 DROP       icmp --  *      *       0.0.0.0/0            0.0.0.0/0            icmptype 8
   32  2373 LOG        all  --  *      *       0.0.0.0/0            0.0.0.0/0            limit: avg 5/sec burst 5 LOG flags 0 level 6 prefix "Inbound "
   32  2373 DROP       all  --  *      *       0.0.0.0/0            0.0.0.0/0           

Chain LSO (0 references)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 LOG_FILTER  all  --  *      *       0.0.0.0/0            0.0.0.0/0           
    0     0 LOG        all  --  *      *       0.0.0.0/0            0.0.0.0/0            limit: avg 5/sec burst 5 LOG flags 0 level 6 prefix "Outbound "
    0     0 REJECT     all  --  *      *       0.0.0.0/0            0.0.0.0/0            reject-with icmp-port-unreachable

Chain OUTBOUND (1 references)
 pkts bytes target     prot opt in     out     source               destination         
    4   336 ACCEPT     icmp --  *      *       0.0.0.0/0            0.0.0.0/0           
 375K   20M ACCEPT     tcp  --  *      *       0.0.0.0/0            0.0.0.0/0            state RELATED,ESTABLISHED
  331 25140 ACCEPT     udp  --  *      *       0.0.0.0/0            0.0.0.0/0            state RELATED,ESTABLISHED
 7583  563K ACCEPT     all  --  *      *       0.0.0.0/0            0.0.0.0/0           

I'm completely out of ideas (and helpful links) at this point. Any/All suggestions, hints, or encouraging words of sympathy would be appreciated at this point!

Cheers, Mike

share|improve this question
    
Firewall? What's the output of sudo iptables -L -nv? If it's too long, upload it to paste.ubuntu.com. –  Eric Carvalho May 27 '13 at 19:20
    
And as always in such a case: try ssh localhost and tell us the outcome. –  guntbert May 27 '13 at 20:47
    
@guntbert, ssh localhost works. Should have emphasized that in the question. –  Mike B May 27 '13 at 21:20
    
@EricCarvalho I've added the iptables output above. A couple of 'state INVALID' lines jump out at me. –  Mike B May 27 '13 at 21:31

1 Answer 1

This was caused by Firestarter, which I had forgotten was even installed on this machine. Removing it and rebooting has solved the issue.

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