From: Sippel, Christian (Christian.Sippel@IZB.DE)
Date: Tue Jul 29 2003 - 05:00:02 EDT
Dear list,
I have the following routing problem:
An AIX 5.1-Box has 2 IP adresses in the same subnet, 172.16.125.121 and
172.16.125.123. Both are on the same adapter, en0, .121 als "real" adress,
.123 as an alias. I would like to send mails to an Exchange-Server with the
IP 1.4.13.29 which is behind a firewall. If I do for example a traceroute to
1.4.13.29 my box uses its .121-adress.
I tried the following
route add -host 1.4.13.29 -interface 172.16.125.123
then netstat -rn tells me:
Routing tables
Destination Gateway Flags Refs Use If PMTU Exp
Groups
Route Tree for Protocol Family 2 (Internet):
default 172.16.125.97 UG 10 2347933 en0 - -
1.4.13.29 172.16.125.123 UH 0 44 en0 - -
127/8 127.0.0.1 U 7 828343 lo0 - -
172.16.125.96/27 172.16.125.123 U 2 1889714 en0 - -
172.16.125.121 127.0.0.1 UGHS 5 12027 lo0 - -
172.16.125.123 127.0.0.1 UGHS 4 12036 lo0 - -
172.16.125.128/25 172.16.125.143 U 7 1592778 en1 - -
172.16.125.143 127.0.0.1 UGHS 42 2070163 lo0 - -
a traceroute says
# traceroute 1.4.13.29
trying to get source for 1.4.13.29
source should be 172.16.125.123
traceroute to 1.4.13.29 (1.4.13.29) from 172.16.125.123 (172.16.125.123), 30
hops max
outgoing MTU = 1500
1 * * *
2 * * *
3 * * *
4 * * *
5 *
but with iptrace I can see that my box doesn't send anything at all - it
behave as if it would miss a route. Also the Firewall-guys tell me nothing
is received by the firewall.
I'm guessing my box "thinks" it could reach the destination IP 1.4.13.29
via a local interface and then sends ARP-Requests for the 1.4.13.29 which
aren't forwarded by the firewall - but I'm not shure about what's going on.
So how can I tell my box if it wants to reach 1.4.13.29 to use it's
sender-IP .123 and the default gateway?
Any help is really appreciated, thanks a lot,
Christian
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