From: Michael Snyder (msnyder@revolutioncomputer.com)
Date: Mon Feb 23 2004 - 11:57:12 GMT-3
I wish I had Trinity as my ccna instructor.
Is there a way to see the present status of the ip helper and/or
forwarding ports?
I'm assume the directed broadcast is just the net address instead of a
unicast address.
-----Original Message-----
From: Church, Chuck [mailto:cchurch@wamnetgov.com]
Sent: Monday, February 23, 2004 8:35 AM
To: Casey, Paul (6822); Michael Snyder; ccielab@groupstudy.com
Cc: Bala Ganesh
Subject: RE: IP forward protocol
Paul,
From your original question, if you wanted to get TFTP
broadcasts from one side of the network to another, you need a
destination address to send the broadcasts to. IP helper converts
all-nets broadcasts to either a unicast, or a directed broadcast. You
could enter the broadcast address of R1's eth0 interface as the helper
destination. Now R5 will convert those 8 UDP broadcasts to directed
broadcasts and send them towards R1. Everything in between will need to
have forwarding of directed broadcasts enabled. If you ONLY want TFTP
and not the other 7 defaults forwarded, remove them with:
no ip forward-protocol udp 37
no ip forward-protocol udp 49
no ip forward-protocol udp 53
no ip forward-protocol udp 67
no ip forward-protocol udp 68
no ip forward-protocol udp 137
no ip forward-protocol udp 138
Think of 'ip helper' as WHERE, and 'ip forward-protocol' as WHAT. The
WHAT just happens to have 8 enabled by default, and can be added to and
subtracted from at will.
For a humorous look at it, check out: http://www.routergod.com/trinity/
HTH,
Chuck Church
Lead Design Engineer
CCIE #8776, MCNE, MCSE
Wam!Net Government Services
13665 Dulles Technology Dr. Ste 250
Herndon, VA 20171
Office: 703-480-2569
Cell: 703-819-3495
cchurch@wamnetgov.com
PGP key:
http://pgp.mit.edu:11371/pks/lookup?op=index&search=cchurch%40wamnetgov.
com
-----Original Message-----
From: Casey, Paul (6822) [mailto:Paul.Casey@o2.com]
Sent: Monday, February 23, 2004 2:35 AM
To: Church, Chuck; Michael Snyder; ccielab@groupstudy.com
Cc: Bala Ganesh
Subject: RE: IP forward protocol
So I am confused, based on my orginal question, what the answer is now.
Also can someone explain the difference between when I forward one of
the
default 8 ports and when I want to forward another type that is not one
of
the 8 default.
Any help appreciated.
kind regards.
-----Original Message-----
From: Church, Chuck [mailto:cchurch@wamnetgov.com]
Sent: 22 February 2004 17:16
To: Michael Snyder; ccielab@groupstudy.com
Cc: Bala Ganesh
Subject: RE: IP forward protocol
There seems to be a lot of confusion on this subject still. 'IP forward
protocol' by itself doesn't do anything. It only modifies the behavior
of
IP helper addresses used on interfaces. Configuring an IP helper
address on
an interface without any ip forward protocol commands will change the
packets destination address to that configured on the helper address
statement if (1) the original destination address was 255.255.255.255
and
(2) the destination protocol was one of the 7 (I think) that are
forwarded
by default. Changing those 7 (using 'ip forward-protocol' and 'no ip
forward-protocol' statements) will change that behavior for all
interfaces
using a helper address statement. It would block netbios shares if
broadcasts are the only method of name resolution. Not very effective,
versus using access lists.
Chuck Church
Lead Design Engineer
CCIE #8776, MCNE, MCSE
Wam!Net Government Services
13665 Dulles Technology Dr. Ste 250
Herndon, VA 20171
Office: 703-480-2569
Cell: 703-819-3495
cchurch@wamnetgov.com
PGP key:
http://pgp.mit.edu:11371/pks/lookup?op=index&search=cchurch%40wamnetgov.
com
-----Original Message-----
From: Michael Snyder [mailto:msnyder@revolutioncomputer.com]
Sent: Sunday, February 22, 2004 7:52 PM
To: ccielab@groupstudy.com
Cc: 'Bala Ganesh'
Subject: RE: IP forward protocol
Does that mean I can turn off netbios shares using?
no ip forward-protocol netbios-dgm
no ip forward-protocol netbios-ns
no ip forward-protocol netbios-ss
I know someone who has been doing this with an access-list for years.
-----Original Message-----
From: Bala Ganesh [mailto:ganesh@topguntechnologies.com]
Sent: Sunday, February 22, 2004 3:53 PM
To: Casey, Paul (6822); ccielab@groupstudy.com
Subject: Re: IP forward protocol
Hello,
The scenario which you are asking for needs "ip forward-protocol udp
tftp"
on all the routers.
the helper command can be used if you want all of the default UDP prots
to
be forwarded.
----- Original Message -----
From: "Casey, Paul (6822)" <Paul.Casey@o2.com>
To: <ccielab@groupstudy.com>
Sent: Monday, February 23, 2004 3:06 AM
Subject: RE: IP forward protocol
> Hello,
>
> ok, ,say I have eth0--r1---r2---r3----r4----r5-fa0/0
>
> and I want to forward tftp (Trivial File Transfer Protocol (69) )
across
the
> network from r5-fa0/0 to r1-eth0
> how do I do this..?? and not forward all other protocols/.
>
> When and when not, do i use the helper command, and what configuration
do
> the routers in the middle need.
>
> Any help appreciated.
> Kind regards.
>
>
>
>
>
>
************************************************************************
****
************
> Please note as of 31st March 2004 we will not be accepting any email
to
> Digifone.com addresses. From this date please send all emails to
O2.com.
> This E-mail is from O2. The E-mail and any files
> transmitted with it are confidential and may also be privileged and
intended
> solely for the use of the individual or entity to whom they are
addressed.
> Any unauthorised direct or indirect dissemination, distribution or
copying
> of this message and any attachments is strictly prohibited. If you
have
> received the E-mail in error please notify postmaster@O2.com or
> telephone ++ 353 1 6095000.
>
>
************************************************************************
****
*************
>
>
This archive was generated by hypermail 2.1.4 : Fri Mar 05 2004 - 07:13:55 GMT-3