From: Edwards, Andrew M (andrew.m.edwards@boeing.com)
Date: Tue Nov 23 2004 - 21:47:48 GMT-3
And, to add to that...as I learned last week, the default behavior of
the router is not to use DNS round robin like a normal DNS server would
do with multiple A records.
However, you can change that default behavior with "ip domain
round-robin" command.
http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123cgcr/
ipras_r/ip1_i1g.htm#wp1103236
Thanks Marvin. 8)
andy
-----Original Message-----
From: Kirk Graham [mailto:kgraham@instructors.net]
Sent: Tuesday, November 23, 2004 3:36 PM
To: ccielab@groupstudy.com
Subject: Re: DHCP
At 05:03 PM 11/23/2004, ccie2be wrote:
> > And, Windoz hosts can use multiple default gateways. Try the first
> > in the list, if its not resonsive try second, etc.
> >
Just a side trivia note... Windoze only uses the multiple gateways for
TCP
applications since those are connection-oriented. UDP, ICMP, and all
other
IP protocols are connectionless, so only the 1st default-gateway in the
list is attempted.
Cisco routers do the same thing for multiple IP addresses on an "ip
host"
statement.
For example,
Central# configure terminal
Central(config)# ip host branch 172.16.24.1 172.16.25.1 172.16.26.1
172.16.27.1 Central(config)# end
Central# ping branch
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.24.1, timeout is 2 seconds:
..... Success rate is 0 percent (0/5)
Central# traceroute branch
Type escape sequence to abort.
Tracing the route to branch (172.16.24.1)
1 * * *
2 * * *
3 <Ctrl-Shift-6>
Central# telnet branch
Trying branch (172.16.24.1)...
% Destination unreachable; gateway or host down
Trying branch (172.16.25.1)... Open
User Access Verification
Password:
Password:
Branch> logout
Central#
Notice ping (ICMP) and traceroute (UDP) only attempt 172.16.24.1 the 1st
IP
address in the host list. But telnet (TCP) keeps trying till a reachable
IP
is found.
I love useless trivia,
Kirk!
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