Page 2 of 2 FirstFirst 12
Results 11 to 15 of 15

Thread: Can't ping the other PC

  1. #11
    Join Date
    Mar 2006
    Location
    Massachusetts
    Beans
    135
    Distro
    Ubuntu 9.04 Jaunty Jackalope

    Re: Can't ping the other PC

    Quote Originally Posted by Roque View Post
    I added an ethernet adapter (Realtek chipset) to each one of my two PCs and connected them with a crossover cable. I get green light in each adapter, the hardware autonegotiation is successful, and if I boot Knoppix in both computers I certainly can upload the interfaces and ping both PCs without problem. But I can't do this in Ubuntu.

    In Ubuntu with iptables loaded any attempt at pinging gets no response. If I flush iptables and set default policies to ACCEPT, and then issue a ping command, I get a "sendmsg: operation not permitted" message.

    Can anyone help? I really have no idea on what's going on here.
    From strictly a networking perspective, there should be no problem. I suspect the problem is with iptables. Can we see the output of this:

    sudo iptables -L

    WOTP
    You will rue the day...

  2. #12
    Join Date
    Jul 2006
    Beans
    103

    Re: Can't ping the other PC

    Code:
    sudo iptables -L
    
    Chain INPUT (policy DROP)
    target     prot opt source               destination
    DROP       icmp --  anywhere             anywhere            icmp echo-reply
    ACCEPT     all  --  anywhere             anywhere
    DROP       tcp  --  anywhere             anywhere            tcp dpt:www
    DROP       tcp  --  anywhere             anywhere            tcp dpt:ssh
    DROP       tcp  --  anywhere             anywhere            tcp dpt:smtp
    DROP       tcp  --  anywhere             anywhere            tcp dpt:pop3
    DROP       tcp  --  anywhere             anywhere            tcp dpt:domain
    LOG        all  --  anywhere             anywhere            state NEW LOG level warning prefix `Non-requested: '
    DROP       all  --  anywhere             anywhere            state NEW
    LOG        icmp -f  anywhere             anywhere            LOG level warning prefix `Fragmented ICMP: '
    DROP       icmp -f  anywhere             anywhere
    ACCEPT     all  --  anywhere             anywhere            state RELATED,ESTABLISHED
    
    Chain FORWARD (policy DROP)
    target     prot opt source               destination
    
    Chain OUTPUT (policy DROP)
    target     prot opt source               destination
    ACCEPT     icmp --  anywhere             anywhere            icmp echo-request
    ACCEPT     all  --  anywhere             anywhere
    REJECT     tcp  --  anywhere             anywhere            tcp spt:www reject-with icmp-port-unreachable
    REJECT     tcp  --  anywhere             anywhere            tcp spt:ssh reject-with icmp-port-unreachable
    REJECT     tcp  --  anywhere             anywhere            tcp spt:smtp reject-with icmp-port-unreachable
    REJECT     tcp  --  anywhere             anywhere            tcp spt:pop3 reject-with icmp-port-unreachable
    REJECT     tcp  --  anywhere             anywhere            tcp spt:domain reject-with icmp-port-unreachable
    ACCEPT     all  --  anywhere             anywhere            state NEW,RELATED,ESTABLISHED
    The problem persists even if I flush iptables and free all traffic with default policies:
    Code:
    sudo iptables -F
    
    sudo iptables -P INPUT ACCEPT
    sudo iptables -P OUTPUT ACCEPT
    sudo iptables -P FORWARD ACCEPT

  3. #13
    Join Date
    Mar 2006
    Location
    Massachusetts
    Beans
    135
    Distro
    Ubuntu 9.04 Jaunty Jackalope

    Re: Can't ping the other PC

    sudo iptables -F

    sudo iptables -P INPUT ACCEPT
    sudo iptables -P OUTPUT ACCEPT
    sudo iptables -P FORWARD ACCEPT
    So after doing these commands, let's do another sudo iptables -L and see how you rules look afterward.
    You will rue the day...

  4. #14
    Join Date
    Jul 2006
    Beans
    103

    Re: Can't ping the other PC

    Here it is:
    Code:
    iptables -L
    
    Chain INPUT (policy ACCEPT)
    target     prot opt source               destination
    
    Chain FORWARD (policy ACCEPT)
    target     prot opt source               destination
    
    Chain OUTPUT (policy ACCEPT)
    target     prot opt source               destination

  5. #15
    Join Date
    Mar 2006
    Location
    Massachusetts
    Beans
    135
    Distro
    Ubuntu 9.04 Jaunty Jackalope

    Re: Can't ping the other PC

    Quote Originally Posted by Roque View Post
    Here it is:
    Code:
    iptables -L
    
    Chain INPUT (policy ACCEPT)
    target     prot opt source               destination
    
    Chain FORWARD (policy ACCEPT)
    target     prot opt source               destination
    
    Chain OUTPUT (policy ACCEPT)
    target     prot opt source               destination
    I would say that if you don't have another firewall installed you may have found a bug.
    You will rue the day...

Page 2 of 2 FirstFirst 12

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •