Professional Web Applications Themes

SCO OS 5.0.5 and IP aliases - SCO

Hi. This morning I visited a customer who experiences a problem whose details I'd like to share with the group. He uses some SCO OS 5.0.5 servers (+RS505A, OSS497C and OSS600A) to drive some very-powerful SCSI printers. In one of the above servers, operating as a dual host box (ie, with 2 Nics), he wanted to set up an IP alias on one of the available nic. He used the "ifconfig net1 alias <new_ip> netmask <netmask> broadcast <bcast>" as to set it up and, after verifying the setup with "ifconfig -a", he tried to ping a local printer whose IP ...

  1. #1

    Default SCO OS 5.0.5 and IP aliases

    Hi.

    This morning I visited a customer who experiences a problem whose
    details I'd like to share with the group.

    He uses some SCO OS 5.0.5 servers (+RS505A, OSS497C and OSS600A) to
    drive some very-powerful SCSI printers.

    In one of the above servers, operating as a dual host box (ie, with 2
    Nics), he wanted to set up an IP alias on one of the available nic.

    He used the "ifconfig net1 alias <new_ip> netmask <netmask> broadcast
    <bcast>" as to set it up and, after verifying the setup with "ifconfig
    -a", he tried to ping a local printer whose IP address had the same
    network ID of the alias itself.

    ping seemed to hang, in the sense that packets got transmitted from the
    OS5 box but never returned to it.

    From what the customer was able to observe with a sniffer, the ICMP
    ping packet went out with the IP address of the "real" NIC and not with
    the one of the aliased interface.

    As an example, supposing net1 was configured as

    192.168.10.1/24

    and the aliased IP it was

    192.168.20.1/24

    he was able to capture an ICMP packet sent to (eg) 192.168.20.51 (the IP
    of the network printer) with a source IP set to 192.168.10.1 instead of
    the aliased one.

    A "ping -r 192.168.20.51" was correctly returned so at this point I
    thought about a routing issue.

    Some additional info: on another server (with the very same HW/SW
    config) but operating on a different network, the aliased IP worked
    swimmingly well. I checked the output from "ifconfig -a" and "netstat
    -nr" on both boxes but, from what I can tell, they are pretty similar
    (well, except for the different IP addresses, of course).

    I tried by issuing the "route add -host 192.168.20.51 192.168.20.1"
    command but unsuccessfully; I've also checked that, as per "netstat -nr"
    output, the aliased IP is routed to the 127.0.0.1 interface and the
    192.168.20 network was routed via the 192.168.20.1 interface, which is
    the same config I observed on the second server.

    routed was __NOT__ active at the moment of the configuration (nor was it
    previously).

    I checked "netconfig" on the "offending" machine and I've checked that
    the TCP/IP stack associated to both NICs has the "Advanced Options ->
    Act as a Gateway" set to NO but the same went for the box under which
    the aliasing worked fine.

    My idea was to modify it as to report "Yes", relink and reboot but I was
    not allowed to do that (even if I'm not sure about that).

    The only think I noticed is that, due to some bad network planning, net1
    was set to a non-reserved network ID (ie, it was not 192.168.x as above
    explained) but the customer assured me that the OS5 box is __NOT__
    configured nor allowed to access the Internet (it's on a private network
    LAN).

    If anyone's interested in the "real" details (ie, the real IP addressed
    being used), I'd be happy to share 'em via privare email.

    Thanks for your time.

    Best,
    Roberto
    --
    Roberto Zini - Technical Support Manager - email:r.zini<AT>strhold.it
    Technical Support Manager -- Strhold Evolution Division R.E. (ITALY)
    ---------------------------------------------------------------------
    "Has anybody around here seen an aircraft carrier?"
    (Pete "Maverick" Mitchell - Top Gun)

    Roberto Guest

  2. #2

    Default Re: SCO OS 5.0.5 and IP aliases

    Roberto Zini wrote: 

    Well I never heard of SCSI printers before, you must mean network printer...

    What does the arp table think of all this?

    /dev/null Guest

  3. #3

    Default RE: SCO OS 5.0.5 and IP aliases


     

    Ciao Roberto,

    I always get ipalias-ing wrong on my own, so I always use a little cheat:

    /usr/internet/etc/ipal -n ipaddress

    will spit out the proper command(s) you need to issue to get the IP alias
    working correctly. (Sometimes it requires an arp command, sometimes not. I
    believe if the alias is in the same subnet as the real IP, then an arp is
    required.)

    Good luck,
    Fabio

    Fabio Guest

  4. Moderated Post

    Default Re: SCO OS 5.0.5 and IP aliases

    Removed by Administrator
    Mike Guest
    Moderated Post

  5. #5

    Default Re: SCO OS 5.0.5 and IP aliases

    On Sun, 12 Oct 2003 13:42:11 GMT, Mike Brown <ca> wrote: 

    It's very easy to make outgoing packets have the correct source address
    according to their destination with the iproute2 tools ..... Oh wait,
    that's LINUX tool. When will SCO catch up? Maybe all those developers that
    Bela keeps talking about will fix it for you...

    Joe Guest

  6. Moderated Post

    Default Re: SCO OS 5.0.5 and IP aliases

    Removed by Administrator
    Stuart Guest
    Moderated Post

  7. #7

    Default Re: SCO OS 5.0.5 and IP aliases

    /dev/null wrote: [/ref]

    [snip]
     

    Well, that was my first time I stumbled across a SCSI printer and, trust
    me, they're SCSI printers indeed (no NETWORK ones).
     

    asp -a shows the correct MAC address associated to the printer's IP address.

    Thanks,
    Roberto
    --
    Roberto Zini - Technical Support Manager - email:r.zini<AT>strhold.it
    Technical Support Manager -- Strhold Evolution Division R.E. (ITALY)
    ---------------------------------------------------------------------
    "Has anybody around here seen an aircraft carrier?"
    (Pete "Maverick" Mitchell - Top Gun)

    Roberto Guest

  8. #8

    Default Re: SCO OS 5.0.5 and IP aliases

    Fabio Giannotti wrote: 

    Fabio,

    thanks for your tip.

    I'll issue the above command on the customer's box and I'll report my
    findings back to the group.

    Best,
    Roberto
    --
    Roberto Zini - Technical Support Manager - email:r.zini<AT>strhold.it
    Technical Support Manager -- Strhold Evolution Division R.E. (ITALY)
    ---------------------------------------------------------------------
    "Has anybody around here seen an aircraft carrier?"
    (Pete "Maverick" Mitchell - Top Gun)

    Roberto Guest

  9. Moderated Post

    Default Re: SCO OS 5.0.5 and IP aliases

    Removed by Administrator
    Roberto Guest
    Moderated Post

  10. #10

    Default Re: SCO OS 5.0.5 and IP aliases

    Fabio Giannotti wrote: [/ref]

    [snip]
     

    Fabio,

    thanks for the advice but unfortunately it does not work even by
    changing the interface name (ipal sticks to the first one) and its MAC
    address.

    Again, a simple "ping -r" does work.

    Thanks,
    Roberto
    --
    Roberto Zini - Technical Support Manager - email:r.zini<AT>strhold.it
    Technical Support Manager -- Strhold Evolution Division R.E. (ITALY)
    ---------------------------------------------------------------------
    "Has anybody around here seen an aircraft carrier?"
    (Pete "Maverick" Mitchell - Top Gun)

    Roberto Guest

Similar Threads

  1. RFC: field::aliases
    By Kevin Michael Vail in forum PERL Modules
    Replies: 2
    Last Post: September 28th, 01:24 AM
  2. Aliases in Perl?
    By Jeff Westman in forum PERL Beginners
    Replies: 4
    Last Post: October 20th, 04:41 PM
  3. IP-Addresses and aliases
    By Friedhelm Neyer in forum AIX
    Replies: 3
    Last Post: August 6th, 03:49 PM

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
  •  

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139