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Re: Lost connection

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  • Hal F. Gottfried
    I am heading out on business all next week, I ll connect from the hotel on my laptop and look over your session and information. I have Windows and Solaris on
    Message 1 of 5 , Apr 1, 2001
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      I am heading out on business all next week, I'll connect from the hotel on
      my laptop and look over your session and information. I have Windows and
      Solaris on my laptop so maybe I can check a few things I am thinking off.
      Also on Monday send me your syslogs from the Scoop and Sniffer if you can so
      I check my theories.

      - H

      ----- Original Message -----
      From: "M B" <moncef2@...>
      To: <tcp-impl@...>
      Sent: Sunday, April 01, 2001 2:34 AM
      Subject: Re: Lost connection


      >
      > At the time the problem fall on my lap I had no access to any of the
      > implicated servers! But I can answer your question: The Sun server is
      > an E450 running Solaris 2.6. The client is an x86 running NT 4.
      >
      > On Monday once I get access to these machines, I will put a sniffer
      > on the NT side, then run a snoop on the Sun server. Here is all the
      > information I have so far:
      >
      > LAN1.....T1.....LAN2.....FR.....LAN3
      >
      > . T1 = T1 link.
      > . FR = Frame Relay.
      > . LAN1 = Network where the NT machine resides.
      > . LAN3 = Network where the Sun machine resides.
      > . LAN2 = The network between the two Networks. LAN2 and LAN3
      > are privately connected. No other possible path from LAN1
      > to LAN3 other than LAN2.
      > . LAN1, LAN2 and LAN 3 are 100Base-T.
      > . FTP transfers between LAN1 and LAN2 succeed.
      > . FTP transfers between LAN2 and LAN3 succeed.
      > . FTP transfers between LAN1 and LAN3 fail.
      >
      > 1- Here is the log of a typical ftp session (look at the time stamps):
      > <BEGIN>
      > Mar 30 10:44:54 oh44ux01 ftpd[21340]: FTPD: connection from 172.28.2.7 at
      > Fri Mar 30 10:44:54 2001
      > Mar 30 10:44:54 oh44ux01 ftpd[21340]: <--- 220
      > Mar 30 10:44:54 oh44ux01 ftpd[21340]: oh44ux01 FTP server (SunOS 5.6)
      ready.
      > Mar 30 10:44:59 oh44ux01 ftpd[21340]: FTPD: command: USER test
      > Mar 30 10:44:59 oh44ux01 ftpd[21340]: <--- 331
      > Mar 30 10:44:59 oh44ux01 ftpd[21340]: Password required for test.
      > Mar 30 10:45:04 oh44ux01 ftpd[21340]: FTPD: command: PASS <passwd>
      > Mar 30 10:45:04 oh44ux01 ftpd[21340]: <--- 230
      > Mar 30 10:45:04 oh44ux01 ftpd[21340]: User test logged in.
      > Mar 30 10:45:14 oh44ux01 ftpd[21340]: FTPD: command: TYPE I
      > Mar 30 10:45:14 oh44ux01 ftpd[21340]: <--- 200
      > Mar 30 10:45:14 oh44ux01 ftpd[21340]: Type set to I.
      > Mar 30 10:45:22 oh44ux01 ftpd[21340]: FTPD: command: PORT 172,28,2,7,10,64
      > Mar 30 10:45:22 oh44ux01 ftpd[21340]: <--- 200
      > Mar 30 10:45:22 oh44ux01 ftpd[21340]: PORT command successful.
      > Mar 30 10:45:22 oh44ux01 ftpd[21340]: FTPD: command: STOR
      00000100006002.pdf
      > Mar 30 10:45:23 oh44ux01 ftpd[21340]: <--- 150
      > Mar 30 10:45:23 oh44ux01 ftpd[21340]: Binary data connection for
      > 00000100006002.pdf (172.28.2.7,2624).
      > Mar 30 12:56:51 oh44ux01 ftpd[21340]: lost connection
      > <END>
      >
      > 2- Another session where several files were transfered then there was a
      time
      > out:
      >
      > [cut]
      > Mar 27 17:09:49 oh44ux01 ftpd[6915]: <--- 150
      > Mar 27 17:09:49 oh44ux01 ftpd[6915]: ASCII data connection for /bin/ls
      > (172.28.2.7,2115) (0 bytes).
      > Mar 27 17:09:49 oh44ux01 ftpd[6915]: <--- 226
      > Mar 27 17:09:49 oh44ux01 ftpd[6915]: ASCII Transfer complete.
      > Mar 27 17:12:49 oh44ux01 ftpd[6915]: FTPD: command: NOOP
      > Mar 27 17:12:49 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:12:49 oh44ux01 ftpd[6915]: NOOP command successful.
      > Mar 27 17:15:49 oh44ux01 ftpd[6915]: FTPD: command: NOOP
      > Mar 27 17:15:49 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:15:49 oh44ux01 ftpd[6915]: NOOP command successful.
      > Mar 27 17:15:55 oh44ux01 ftpd[6915]: FTPD: command: TYPE I
      > Mar 27 17:15:55 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:15:55 oh44ux01 ftpd[6915]: Type set to I.
      > Mar 27 17:15:55 oh44ux01 ftpd[6915]: FTPD: command: PORT 172,28,2,7,8,214
      > Mar 27 17:15:55 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:15:55 oh44ux01 ftpd[6915]: PORT command successful.
      > Mar 27 17:15:55 oh44ux01 ftpd[6915]: FTPD: command: STOR
      00000184159044.pdf
      > Mar 27 17:15:56 oh44ux01 ftpd[6915]: <--- 150
      > Mar 27 17:15:56 oh44ux01 ftpd[6915]: Binary data connection for
      > 00000184159044.pdf (172.28.2.7,2262).
      > Mar 27 17:15:56 oh44ux01 ftpd[6915]: <--- 226
      > Mar 27 17:15:56 oh44ux01 ftpd[6915]: Transfer complete.
      > Mar 27 17:15:56 oh44ux01 ftpd[6915]: FTPD: command: TYPE I
      > Mar 27 17:15:56 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:15:56 oh44ux01 ftpd[6915]: Type set to I.
      > Mar 27 17:15:56 oh44ux01 ftpd[6915]: FTPD: command: PORT 172,28,2,7,8,215
      > Mar 27 17:15:56 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:15:56 oh44ux01 ftpd[6915]: PORT command successful.
      > Mar 27 17:15:56 oh44ux01 ftpd[6915]: FTPD: command: STOR
      00000190101016.pdf
      > Mar 27 17:15:56 oh44ux01 ftpd[6915]: <--- 150
      > Mar 27 17:15:56 oh44ux01 ftpd[6915]: Binary data connection for
      > 00000190101016.pdf (172.28.2.7,2263).
      > Mar 27 17:15:57 oh44ux01 ftpd[6915]: <--- 226
      > Mar 27 17:15:57 oh44ux01 ftpd[6915]: Transfer complete.
      > Mar 27 17:15:57 oh44ux01 ftpd[6915]: FTPD: command: TYPE I
      > Mar 27 17:15:57 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:15:57 oh44ux01 ftpd[6915]: Type set to I.
      > Mar 27 17:15:57 oh44ux01 ftpd[6915]: FTPD: command: PORT 172,28,2,7,8,216
      > Mar 27 17:15:57 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:15:57 oh44ux01 ftpd[6915]: PORT command successful.
      > Mar 27 17:15:57 oh44ux01 ftpd[6915]: FTPD: command: STOR
      00000192097033.pdf
      > Mar 27 17:15:57 oh44ux01 ftpd[6915]: <--- 150
      > Mar 27 17:15:57 oh44ux01 ftpd[6915]: Binary data connection for
      > 00000192097033.pdf (172.28.2.7,2264).
      > Mar 27 17:15:58 oh44ux01 ftpd[6915]: <--- 226
      > Mar 27 17:15:58 oh44ux01 ftpd[6915]: Transfer complete.
      > Mar 27 17:15:58 oh44ux01 ftpd[6915]: FTPD: command: TYPE I
      > Mar 27 17:15:58 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:15:58 oh44ux01 ftpd[6915]: Type set to I.
      > Mar 27 17:15:58 oh44ux01 ftpd[6915]: FTPD: command: PORT 172,28,2,7,8,217
      > Mar 27 17:15:58 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:15:58 oh44ux01 ftpd[6915]: PORT command successful.
      > Mar 27 17:15:58 oh44ux01 ftpd[6915]: FTPD: command: STOR
      00000192213008.pdf
      > Mar 27 17:15:58 oh44ux01 ftpd[6915]: <--- 150
      > Mar 27 17:15:58 oh44ux01 ftpd[6915]: Binary data connection for
      > 00000192213008.pdf (172.28.2.7,2265).
      > Mar 27 17:15:59 oh44ux01 ftpd[6915]: <--- 226
      > Mar 27 17:15:59 oh44ux01 ftpd[6915]: Transfer complete.
      > Mar 27 17:15:59 oh44ux01 ftpd[6915]: FTPD: command: TYPE I
      > Mar 27 17:15:59 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:15:59 oh44ux01 ftpd[6915]: Type set to I.
      > Mar 27 17:15:59 oh44ux01 ftpd[6915]: FTPD: command: PORT 172,28,2,7,8,219
      > Mar 27 17:15:59 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:15:59 oh44ux01 ftpd[6915]: PORT command successful.
      > Mar 27 17:15:59 oh44ux01 ftpd[6915]: FTPD: command: STOR
      00000196271002.pdf
      > Mar 27 17:15:59 oh44ux01 ftpd[6915]: <--- 150
      > Mar 27 17:15:59 oh44ux01 ftpd[6915]: Binary data connection for
      > 00000196271002.pdf (172.28.2.7,2267).
      > Mar 27 17:16:00 oh44ux01 ftpd[6915]: <--- 226
      > Mar 27 17:16:00 oh44ux01 ftpd[6915]: Transfer complete.
      > Mar 27 17:16:00 oh44ux01 ftpd[6915]: FTPD: command: TYPE I
      > Mar 27 17:16:00 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:16:00 oh44ux01 ftpd[6915]: Type set to I.
      > Mar 27 17:16:00 oh44ux01 ftpd[6915]: FTPD: command: PORT 172,28,2,7,8,220
      > Mar 27 17:16:00 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:16:00 oh44ux01 ftpd[6915]: PORT command successful.
      > Mar 27 17:16:00 oh44ux01 ftpd[6915]: FTPD: command: STOR
      00000198177007.pdf
      > Mar 27 17:16:00 oh44ux01 ftpd[6915]: <--- 150
      > Mar 27 17:16:00 oh44ux01 ftpd[6915]: Binary data connection for
      > 00000198177007.pdf (172.28.2.7,2268).
      > Mar 27 17:16:01 oh44ux01 ftpd[6915]: <--- 226
      > Mar 27 17:16:01 oh44ux01 ftpd[6915]: Transfer complete.
      > Mar 27 17:16:01 oh44ux01 ftpd[6915]: FTPD: command: TYPE I
      > Mar 27 17:16:01 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:16:01 oh44ux01 ftpd[6915]: Type set to I.
      > Mar 27 17:16:01 oh44ux01 ftpd[6915]: FTPD: command: PORT 172,28,2,7,8,221
      > Mar 27 17:16:01 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:16:01 oh44ux01 ftpd[6915]: PORT command successful.
      > Mar 27 17:16:01 oh44ux01 ftpd[6915]: FTPD: command: STOR
      00000198191008.pdf
      > Mar 27 17:16:01 oh44ux01 ftpd[6915]: <--- 150
      > Mar 27 17:16:01 oh44ux01 ftpd[6915]: Binary data connection for
      > 00000198191008.pdf (172.28.2.7,2269).
      > Mar 27 17:16:02 oh44ux01 ftpd[6915]: <--- 226
      > Mar 27 17:16:02 oh44ux01 ftpd[6915]: Transfer complete.
      > Mar 27 17:16:02 oh44ux01 ftpd[6915]: FTPD: command: TYPE I
      > Mar 27 17:16:02 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:16:02 oh44ux01 ftpd[6915]: Type set to I.
      > Mar 27 17:16:02 oh44ux01 ftpd[6915]: FTPD: command: PORT 172,28,2,7,8,223
      > Mar 27 17:16:02 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 17:16:02 oh44ux01 ftpd[6915]: PORT command successful.
      > Mar 27 17:16:02 oh44ux01 ftpd[6915]: FTPD: command: STOR
      00000199138008.pdf
      > Mar 27 17:16:02 oh44ux01 ftpd[6915]: <--- 150
      > Mar 27 17:16:02 oh44ux01 ftpd[6915]: Binary data connection for
      > 00000199138008.pdf (172.28.2.7,2271).
      > Mar 27 19:27:28 oh44ux01 ftpd[6915]: <--- 552
      > Mar 27 19:27:28 oh44ux01 ftpd[6915]: 00000199138008.pdf: Connection timed
      > out.
      > Mar 27 19:27:28 oh44ux01 ftpd[6915]: FTPD: command: TYPE I
      > Mar 27 19:27:28 oh44ux01 ftpd[6915]: <--- 200
      > Mar 27 19:27:28 oh44ux01 ftpd[6915]: Type set to I.
      > Mar 27 19:27:28 oh44ux01 ftpd[6915]: <--- 221
      > Mar 27 19:27:28 oh44ux01 ftpd[6915]: You could at least say goodbye.
      > <END>
      > _________________________________________________________________
      > Get your FREE download of MSN Explorer at http://explorer.msn.com
      >
      >
    • Jon Snader
      ... [another example deleted] I notice that in both cases the connection drops after about 2 hours into a data transfer, and that the control connection
      Message 2 of 5 , Apr 1, 2001
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        On Sun, Apr 01, 2001 at 01:34:10AM -0500, M B wrote:
        >
        > At the time the problem fall on my lap I had no access to any of the
        > implicated servers! But I can answer your question: The Sun server is
        > an E450 running Solaris 2.6. The client is an x86 running NT 4.
        >
        > On Monday once I get access to these machines, I will put a sniffer
        > on the NT side, then run a snoop on the Sun server. Here is all the
        > information I have so far:
        >
        > LAN1.....T1.....LAN2.....FR.....LAN3
        >
        > . T1 = T1 link.
        > . FR = Frame Relay.
        > . LAN1 = Network where the NT machine resides.
        > . LAN3 = Network where the Sun machine resides.
        > . LAN2 = The network between the two Networks. LAN2 and LAN3
        > are privately connected. No other possible path from LAN1
        > to LAN3 other than LAN2.
        > . LAN1, LAN2 and LAN 3 are 100Base-T.
        > . FTP transfers between LAN1 and LAN2 succeed.
        > . FTP transfers between LAN2 and LAN3 succeed.
        > . FTP transfers between LAN1 and LAN3 fail.
        >
        > 1- Here is the log of a typical ftp session (look at the time stamps):
        > <BEGIN>
        > Mar 30 10:44:54 oh44ux01 ftpd[21340]: FTPD: connection from 172.28.2.7 at
        > Fri Mar 30 10:44:54 2001
        > Mar 30 10:44:54 oh44ux01 ftpd[21340]: <--- 220
        > Mar 30 10:44:54 oh44ux01 ftpd[21340]: oh44ux01 FTP server (SunOS 5.6) ready.
        > Mar 30 10:44:59 oh44ux01 ftpd[21340]: FTPD: command: USER test
        > Mar 30 10:44:59 oh44ux01 ftpd[21340]: <--- 331
        > Mar 30 10:44:59 oh44ux01 ftpd[21340]: Password required for test.
        > Mar 30 10:45:04 oh44ux01 ftpd[21340]: FTPD: command: PASS <passwd>
        > Mar 30 10:45:04 oh44ux01 ftpd[21340]: <--- 230
        > Mar 30 10:45:04 oh44ux01 ftpd[21340]: User test logged in.
        > Mar 30 10:45:14 oh44ux01 ftpd[21340]: FTPD: command: TYPE I
        > Mar 30 10:45:14 oh44ux01 ftpd[21340]: <--- 200
        > Mar 30 10:45:14 oh44ux01 ftpd[21340]: Type set to I.
        > Mar 30 10:45:22 oh44ux01 ftpd[21340]: FTPD: command: PORT 172,28,2,7,10,64
        > Mar 30 10:45:22 oh44ux01 ftpd[21340]: <--- 200
        > Mar 30 10:45:22 oh44ux01 ftpd[21340]: PORT command successful.
        > Mar 30 10:45:22 oh44ux01 ftpd[21340]: FTPD: command: STOR 00000100006002.pdf
        > Mar 30 10:45:23 oh44ux01 ftpd[21340]: <--- 150
        > Mar 30 10:45:23 oh44ux01 ftpd[21340]: Binary data connection for
        > 00000100006002.pdf (172.28.2.7,2624).
        > Mar 30 12:56:51 oh44ux01 ftpd[21340]: lost connection
        > <END>
        >

        [another example deleted]

        I notice that in both cases the connection drops after about 2 hours into
        a data transfer, and that the control connection appears to be idle for
        that time. I have seen examples where stateful firewalls or NAT devices
        will time out idle connections after time intervals that are typically
        in the 2 hour range. Have you investigated this possibility?

        Jon Snader
      • M B
        Jon, You re right. There is a Check Point firewall between LAN2 and LAN3. And it translates all IPs coming from LAN1 and LAN2. As you said, that would explain
        Message 3 of 5 , Apr 1, 2001
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          Jon,
          You're right. There is a Check Point firewall between LAN2 and LAN3.
          And it translates all IPs coming from LAN1 and LAN2. As you said,
          that would explain why a connection gets dropped after being idle
          for 2 hours or so.

          LAN1....T1.....LAN2-FW-......FR.....LAN3

          But why would an FTP transfer go idle if it's coming from LAN1, while
          FTP transfers from LAN2 finish normally? More info:
          . LAN1 and LAN2 don't have any firewall between them.
          . The problem started to occur only after the NT machine was moved
          from LAN2 to LAN1.

          Thanks guys for your contributions. It's helpful to brainstorm before
          zeroing on something.

          _________________________________________________________________
          Get your FREE download of MSN Explorer at http://explorer.msn.com
        • Tirumala, Srivathsa (Srivathsa)
          ... From your examples, its not clear that the control connection is the one that s being closed. Your example 2 shows that after one file xfer fails, you
          Message 4 of 5 , Apr 2, 2001
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            >
            > Jon,
            > You're right. There is a Check Point firewall between LAN2 and LAN3.
            > And it translates all IPs coming from LAN1 and LAN2. As you said,
            > that would explain why a connection gets dropped after being idle
            > for 2 hours or so.
            >
            > LAN1....T1.....LAN2-FW-......FR.....LAN3

            From your examples, its not clear that the control connection is the one
            that's being closed. Your example 2 shows that after one file xfer fails,
            you still send a TYPE command on the control connection.. and this is
            accepted by the server!! So the control connection is still up. And
            obviously, the data connection is not idle.

            >
            > But why would an FTP transfer go idle if it's coming from LAN1, while
            > FTP transfers from LAN2 finish normally? More info:
            > . LAN1 and LAN2 don't have any firewall between them.
            > . The problem started to occur only after the NT machine was moved
            > from LAN2 to LAN1.

            I guess LAN2 to LAN3 transfers take less than 2 hours.

            Bye
            Srivathsa
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