A month ago I posted a question about some trouble I'm having with an ethernet-
interface which I have given two IP-addresses. I received no helping answers
then. Now I'm sending out another plea for help since Digital in Sweden wants
us to pay for getting this problem solved!! (Yes, we have service-contracts on
both hardware and software, but that doesn't seem mean much...)
What I have:
On a couple of 3000/400-machines I have added a second address to the built-in
interface via "ifconfig ... alias". The second address works fine for telnet,
nfs, ftp and so on. These two machines are BIND and NTP-servers. When a
client tries to use these services via the second address it fails.
When I used tcpdump to analyze what really happens to a BIND-request I found
that both request and answer were sent over the network. As far as I could
judge from what tcpdump says the packets are correct. Of some reason the client
does not seem to accept the answer-packets. When the client is on the other
side of a router an icmp-packet returns to the server saying that the
destination port is unreachable. (The IP-address and portnumber are correct!)
The really weird thing is that not all types of clients fail. Macintoshes and
DECstations get answers from the BIND-server. DECstations fail to get any
answers from the NTP-servers. OSF/1- and multia-systems (Windows NT) fail to
use the second address as their BIND-server.
Has anybody out there done something similar? Have I done something wrong? The
systems are running OSF/1 3.0. This is the relevant part of /etc/rc.config from
one system:
NUM_NETCONFIG="4"
MAX_NETDEVS="24"
NETDEV_0="ln0"
NETDEV_1="ln1"
NETDEV_2="ln2"
NETDEV_3="ln0"
NETDEV_4=
NETDEV_5=
NETDEV_6=
NETDEV_7=
IFCONFIG_0="138.221.112.101 netmask 255.255.255.0"
IFCONFIG_1="138.221.113.46 netmask 255.255.255.0"
IFCONFIG_2="138.221.114.41 netmask 255.255.255.0"
IFCONFIG_3="138.221.115.66 netmask 255.255.255.0 alias"
IFCONFIG_4=
IFCONFIG_5=
IFCONFIG_6=
IFCONFIG_7=
RWHOD="no"
ROUTED="yes"
ROUTED_FLAGS="-q"
ROUTER="no"
GATED="no"
GATED_FLAGS=
/Mats
===============================================================================
Mats G Karlsson E-mail: atomaka_at_ato.abb.se (__)
ABB Atom AB MEMO: ABB.SEATO.ATOMAKA (oo)
Avd: AUD Tel: +46 (0)21 347762 \/-------\
S-721 63 Vasteras Fax: +46 (0)21 347088 || | \
Sweden ||---W|| *
===============================================================================
Received on Mon May 29 1995 - 07:51:43 NZST