RE: Frame Relay Switch [7:75019]
You can get a 2522 with 10 port serial for around $500. Raj Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=75022t=75019 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: Flapping on cat 4506 [7:75018]
I don't know how much this is right. BUt if you are running Software Release 12.1(14)E1 there are many Caveats in that release. This might help. If you disable IGMP snooping with a large number of groups and VLANs, CPU HOG and HOST FLAPPING messages might display. The following similar messages will appear. 2d07h: %SYS-3-CPUHOG: Task ran for 8692 msec (0/0), process = Exec, PC = 128790. 2d07h: %C4K_EBM-4-HOSTFLAPPING: Host 00:10:0B:10:B9:20 in vlan 200 is flapping between port Po2 and port Po1 There is no workaround for that, that I know of. Someone could correct me if I am wrong. Raj Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=75021t=75018 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
IP expert's RS workbook [7:74849]
Anyone willing to share there IP experts RS workbook or pitch in to get it together? Raj Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=74849t=74849 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: Stuck on Subinterfaces - HELP! [7:74854]
Use the frame relay for subinterfaces. You use subinterfaces to connect multiple frame relay location to the hub. Raj Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=74857t=74854 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: How many CCIEs in India ?? [7:73010]
Cisco publish CCIE numbers worldwide online. Check this site out for updated list. http://www.cisco.com/warp/public/625/ccie/ccie_program/ccie_present.html Raj Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=73011t=73010 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Vty access class [7:72990]
I think the extended named access list don't allow you to say eq to at the end. Also make sure you have domain-name, rsa key on the router. and then try this. RSA key don't show in the config, to test if you have rsa key try this: router#show crypto key mypubkey rsa then try this. username test password 0 test ip domain-name router.test.com ip ssh time-out 60 ip ssh authentication-retries 2 access-list 101 permit 22 host 10.1.1.2 host 10.1.1.1 line vty 0 4 access-class 101 in login local transport input ssh Hope this helps. Raj:) Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=73022t=72990 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: ios upgrade... [7:72779]
I think its a software error trying to read a memeory block that has gone bad, the older images did nothing when the memory block was bad but skip over, I think the newer images report it. Thats what I think. Could be wrong or could be right. Raj Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=72886t=72779 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: ios upgrade... [7:72779]
I think its a software error trying to read a memeory block that has gone bad, the older images did nothing when the memory block was bad but skip over, I think the newer images report it. Thats what I think. Could be wrong or could be right. Raj Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=72925t=72779 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: ios upgrade... [7:72779]
Here u go! Bus Error Crashes The system encounters a bus error when the processor tries to access a memory location that either does not exist (a software error) or does not respond properly (a hardware problem). A bus error can be identified by looking at the output of the show version command provided by the router (if not power-cycled or manually reloaded). Raj Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=72797t=72779 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Urgent Help On Cisco Radius [7:72617]
Here, http://www.cisco.com/warp/public/cc/pd/iosw/ioft/iolk/tech/rdius_wp.htm This should get u started. This is white papers on Cisco support fro Radius in cisco IOS. Raj Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=72636t=72617 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Prefix-list help [7:72090]
Classless domain -R1--classful domain R1 is the border router between the classless and classful routing domain. R1 maintains a BGP peering session with the classless routing domain, and runs a classful IGP with the classful routing domain. The classless routing domain is originating a default route to R1 via BGP, and advertising prefixes which are subnetted, aggregated, and classful. Since the classful routing domain does not support the advertisement of subnets or aggregates, there is no reason for R1 to accept any of these prefixes in from the classless domain. Configure an access-list or prefix-list on R1 that will only allow classful networks and a default route in from the classless routing domain. This access-list or prefix-list should not contain more than four entries. I think this will work but not sure. Can anyone tell me if this is right? ip prefix-list test seq 5 permit 0.0.0.0/0 ip prefix-list test seq 5 permit 0.0.0.0/0 ge 8 le 8 ip prefix-list test seq 5 permit 0.0.0.0/0 ge 16 le 16 ip prefix-list test seq 5 permit 0.0.0.0/0 ge 24 le 24 Any help is duly appreciated in advance. Thanks Raj Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=72090t=72090 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Prefix-list help [7:72090]
LOL, thanks I got this like 10 mins before I got your email. I went of a search spree, and found the answer. Here is what I found, its all binary. This will permit the default route ip prefix-list test seq 5 permit 0.0.0.0/0 This will look at the first bit of the first octet and will match the netmask to 8 bit ip prefix-list test seq 5 permit 0.0.0.0/1 ge 8 le 8 This will look at the first 2 bits of the first octet 1000 and match the netmask to 16 bit ip prefix-list test seq 5 permit 128.0.0.0/2 ge 16 le 16 This will look at the first 3 bits of the first octet 1100 and match the netmask to 24 bit ip prefix-list test seq 5 permit 192.0.0.0/3 ge 24 le 24 Thank you very much for all your help. Really appreciate it Raj Singh Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=72140t=72090 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IOS file name
Will, Try the following link http://www.cisco.com/warp/public/620/4.html For IOS Naming Conventions. - raj ""Will Guan"" [EMAIL PROTECTED] wrote in message 96vau0$lbs$[EMAIL PROTECTED]">news:96vau0$lbs$[EMAIL PROTECTED]... Hello everyone: Who can tell me where I can get some material which interpret IOS file name. For example: a IOS file c2500-c-1.120-4.bin, the c means what? and so on. Thank you very much. Will Guan _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: 2901
Look up Router on a Stick configurations. - raj ""Circusnuts"" [EMAIL PROTECTED] wrote in message 004f01c09a60$6082d9e0$[EMAIL PROTECTED]">news:004f01c09a60$6082d9e0$[EMAIL PROTECTED]... Same precess as a Cat5K withought the RSM. Yes Phil - Original Message - From: "Craig Lindstrom" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Monday, February 19, 2001 4:35 AM Subject: 2901 Can a 2901 do layer3 switching with an external router? Craig Lindstrom "Build a man a fire and you keep him warm for an evening, set a man on fire and you keep him warm for the rest of his life." _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: alitlle confused.
Need a little more detail ... and yes it could be an access list configuration issue. Can you actually ping from a node in network a the Unix Box in network B that you are attempting to telnet to ? Can you actually ping from the Unix Box in B to the node in Network A ? Can you telnet to the UNIX box in Network B from a host in Network B ? Or of course you can check the access-list settings on the router(s). - raj "Moahzam Durrani" [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... IF THERE ARE 2 DIFFERENT NETWORKS A AND B , AND WE COULD PING FROM NETWORK A TO B , BUT NOT TELNET TO A CERTAIN UNIX BOX ON NETWORK B, IS THIS AN ACCESS-LIST ISSUE OR IS IT AT THE UNIX BOX THAT IS NOT PERMITTING TELNET . Mo Durrani IST WYSE\EDS phone:408-473 1246 [EMAIL PROTECTED] [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: no domain controller available
Jim, You could set up VMPS and VTP to solve the problem. The campus-wide VLAN model provides the flexibility to have statically configured end stations move to a different floor or building within the campus. Cisco's VLAN Membership Policy Server (VMPS) and the VLAN Trunking Protocol (VTP) make this possible. For example, a mobile user plugs a laptop PC into a LAN port in another building. The local Catalyst switch sends a query to the VMPS to determine the access policy and VLAN membership for the user. Then the Catalyst switch adds the user's port to the appropriate VLAN. - raj "Jim Bond" [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... Hello, I have users at different buildings (on different subnets), when they move their laptop to another building, they have to do ip release/renew, otherwise, they won't get new ip address. Swithes are 5000/5500/6500. Port fast is already enabled. Anything needs to be done on PCs? Thanks in advance. Jim __ Do You Yahoo!? Get personalized email addresses from Yahoo! Mail - only $35 a year! http://personal.mail.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: no domain controller available
Jim, Also look at these links they may help. The Basics http://www.cisco.com/univercd/cc/td/doc/product/rtrmgmt/cw2000/fam_prod/user _reg/2_0/urt20/useguide/urt_bscs.htm Planning for User Registration http://www.cisco.com/univercd/cc/td/doc/product/rtrmgmt/cw2000/fam_prod/user _reg/1_2_1/use_reg/ur1plan.htm - raj "Jim Bond" [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... Hello, I have users at different buildings (on different subnets), when they move their laptop to another building, they have to do ip release/renew, otherwise, they won't get new ip address. Swithes are 5000/5500/6500. Port fast is already enabled. Anything needs to be done on PCs? Thanks in advance. Jim __ Do You Yahoo!? Get personalized email addresses from Yahoo! Mail - only $35 a year! http://personal.mail.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Can someone interpret this please?
Kevin and John, A note about the "memory access errors". If the router in question is using a MIPS CPU for example, interrupt processing CPU utlization can also run higher than normal due to an error called an alignment error. Alignment errors occur when the program running on the CPU attempts to access a memory value at an address that violates the memory alignment requirements of the CPU. On MIPS CPUs, 16 bit values must begin at a memory address divisible by 2. 32 bit values must begin at a memory address divisible by 4, and so on. If IOS attempts to access data at an address that violates these restrictions, the CPU generates an exception and calls a special IOS function that retreives the data in segments that don't violate the restrictions. This exception funcation adds MANY more instructions and more CPU time to an otherwise simple operation of accessing a data item. For this reason, alignment errors can have a significant negative impact on performance by consuming extra CPU cycles. You can check the alignment errors by doing a show align from the CLI. - raj ""Kevin Wigle"" [EMAIL PROTECTED] wrote in message 010d01c09520$ff4b7040$[EMAIL PROTECTED]">news:010d01c09520$ff4b7040$[EMAIL PROTECTED]... Dear group, Investigating a router that is starting to loaded down. When I do a sh proc cpu I get 50% or cpu utilization but the stats don't seem to add up to 50%. Is there another way to try and see where the 50% is coming from? sh proc cpu CPU utilization for five seconds: 44%/44%; one minute: 50%; five minutes: 52% PID Runtime(ms) Invoked uSecs5Sec 1Min 5Min TTY Process 1 43764 2491562 17 0.00% 0.00% 0.00% 0 Load Meter 2 11636 3222 0.24% 0.05% 0.01% 66 Virtual Exec 318930504 1542973 12268 0.00% 0.12% 0.11% 0 Check heaps 4 0 1 0 0.00% 0.00% 0.00% 0 Chunk Manager 51876 1047 1791 0.00% 0.00% 0.00% 0 Pool Manager 6 0 2 0 0.00% 0.00% 0.00% 0 Timers 7 0 2 0 0.00% 0.00% 0.00% 0 Serial Backgroun 8 0 1 0 0.00% 0.00% 0.00% 0 OIR Handler 9 22296414731 53 0.00% 0.00% 0.00% 0 Environmental mo 10 218428427878510 0.00% 0.00% 0.00% 0 ARP Input 11 0 2 0 0.00% 0.00% 0.00% 0 DDR Timers 12 0 2 0 0.00% 0.00% 0.00% 0 Dialer event 13 4 2 2000 0.00% 0.00% 0.00% 0 Entity MIB API 14 0 1 0 0.00% 0.00% 0.00% 0 SERIAL A'detect 15 0 1 0 0.00% 0.00% 0.00% 0 Critical Bkgnd 16 1813952 1898284955 0.00% 0.01% 0.00% 0 Net Background 17 280 401698 0.00% 0.00% 0.00% 0 Logger 18 753540 12440407 60 0.00% 0.00% 0.00% 0 TTY Background 19 890280 12440425 71 0.00% 0.00% 0.00% 0 Per-Second Jobs 20 4 2 2000 0.00% 0.00% 0.00% 0 VNM DSPRM MAIN 21 418788 12440411 33 0.00% 0.00% 0.00% 0 Partition Check PID Runtime(ms) Invoked uSecs5Sec 1Min 5Min TTY Process 22 0 1 0 0.00% 0.00% 0.00% 0 Net Input 23 31676 2491564 12 0.00% 0.00% 0.00% 0 Compute load avg 24 6663988207365 32136 0.00% 0.03% 0.00% 0 Per-minute Jobs 25 271380 9070214 29 0.00% 0.00% 0.00% 0 NTP 26 0 2 0 0.00% 0.00% 0.00% 0 ATM OAM Input 27 0 2 0 0.00% 0.00% 0.00% 0 ATM OAM TIMER 28 376484 3755446100 0.00% 0.00% 0.00% 0 ATM Periodic 29 0 1 0 0.00% 0.00% 0.00% 0 ATM ARP INPUT 3041599556 18711784 2223 0.16% 0.33% 0.32% 0 IP Input 31 816012 1448197563 0.00% 0.00% 0.00% 0 CDP Protocol 32 0 1 0 0.00% 0.00% 0.00% 0 Asy FS Helper 33 4 1 4000 0.00% 0.00% 0.00% 0 PPP IP Add Route 34 684 20737 32 0.00% 0.00% 0.00% 0 MOP Protocols 35 0 1 0 0.00% 0.00% 0.00% 0 X.25 Encaps Mana 36 0 1 0 0.00% 0.00% 0.00% 0 MPC Router Proce 37 1579312207411 7614 0.00% 0.00% 0.00% 0 IP Background 38 728 1317552 0.00% 0.00% 0.00% 0 SSCOP Input 39 352 856411 0.00% 0.00% 0.00% 0 SSCOP Output 40 36792210450174 0.00% 0.00% 0.00% 0 SSCOP Timer 41 19659 3322 0.00% 0.00% 0.00% 0 ILMI Input 42 0 1 0 0.00% 0.00% 0.00% 0 SNMP Timers 43 518476167742 3090 0.00% 0.00% 0.00% 0 ILMI Request PID Runtime(ms) Invoked uSecs5Sec 1Min 5Min TTY Process 44 43616205621212
A inquiry about ARP behavior, vendors, and differences
NOTE: Long email / question ... regarding ARP and Proxy ARP behavior with
different vendors OS.
A inquiry about ARP behavior, vendors, and differences.
Does the way a host machine behave during the ARP process differ amongst
different OS manufacturers, in relationship to when Proxy ARP can be
implement and when it can't be.
This inquiry should not be mistaken with "is proxy ARP a good idea or bad
idea" question. I just want to find some behavior facts out. Thanks.
Given the following situation:
ClientA ClientB
| |
||
|
|
X
{ROUTER}
Y
|
|
|-|
|
ClientC
Settings:
ClientA: 192.168.12.5 /24
ClientB: 192.168.12.6 /24
ClientC: 192.168.20.101 /24
Interface X on Router: 192.168.12.1 /24
Interface Y on Router: 192.168.20.1 /24
Proxy ARP enabled on both router interfaces
None of the clients have been configured with a default gateway setting.
The operating systems are Windows 98. (Though if you prefer you can say it
is NT 4.0)
The basic statement that I have a question about:
According to Jeff Doyle's Routing TCP/IP vol. 1, book on page 69-70 in
quotes below -
"... For example, a host 192.168.12.5/24 needs to send a packet to
192.168.20.101/24, but is not configured with default gateway information
and therefore does no know how to reach a router. It may issue an ARP
request for 192.168.20.101; the local router, receiving the request and
knowing how to reach network 192.168.20.0, will issue an ARP reply with it's
own data link identifier in the hardware address field. In effect, the
router has tricked the local host into thinking that the router's interface
is the interface of 192.168.20.101. All packets destined for that address
will be send to the router. ..."
The question itself:
The question I have with this is that under a Windows environment at least
in my experience, The decision making process is as follows when trying to d
o an address resolution (ARP Request).
Sender looks at it's own IP address and Subnet Mask compares it to the
target machines IP address to determine if on the same subnetwork. If it is
so . an ARP request is issued. But if the Sender's IP address and the Target
's IP address are not part of the same subnetwork . the sending machine
looks for it's default gateway and does an ARP request for it.
Thus the problem is . if there is no default gateway setup for the sender .
It won't even attempt to do an ARP request . it will IMMEDIATELY say .
Destination host unreachable.
Demonstration 1:
ClientA: 192.168.12.5 /24 PINGSClientC: 192.168.20.101 /24
Notice in the PING results below, where Client A pinging Client C, with the
start and end time there is only a 6/100ths of a second difference from the
start of the ping statement to it informing us no can do. Also note with a
sniffer on the line there are no packets generated either from the pinging
machine.
Current time is 4:25:34.81p -- Start Time
Pinging 192.168.20.101 with 32 bytes of data:
Destination host unreachable.
Destination host unreachable.
Destination host unreachable.
Destination host unreachable.
Ping statistics for 192.168.20.101:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms
Current time is 4:25:34.87p -- End Time
--
Demonstration 2:
ClientA: 192.168.12.5 /24 PINGS192.168.12.88 (non-existent client)
On the other hand if Client A attempts to ping a machine that it believes
has an IP address on the same subnet the following results would occur.
(Given the IP address being pinged is actually in the range of valid address
for that subnet ... but is not in use at the current moment).
You would get the message "Request timed out". By the way notice the start
and end time below. I can show a sniffer capture also .. but won't . there
are actual packets that left the pinging machines interface (ARP requests).
Current time is 4:28:11.41p -- Start time
Pinging 192.168.12.88 with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Ping statistics for 192.168.12.88:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms
Current time is 4:28:29.09p -- End Time
Demonstration 3:
ClientA: 192.168.12.5 /24 PINGSClientB: 192.168.12.6 /24
A normal ping on the same subnet, works as expected.
Current time is 5:26:32.85p
Pinging 192.168.12.6 with 32 bytes of data:
Reply from 192.168.12.6: bytes=32 time=1ms TTL=128
Reply from 192.168.12.6: bytes=32 time10ms TTL=128
Reply from 192.168.12.6: bytes=32 time10ms TTL=128
Reply from 192.168.12.6: bytes=32 time10ms TTL=128
Ping statistics for 192.168.12.6:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in
Re: A inquiry about ARP behavior, vendors, and differences
Thanks for confirming my suspicions, though one question on the part about
setting the default gateway on a host to point to it's own ip address ...
would it behave the same way if the default gateway was set to a loopback
address of 127.x.x.x also. Or did that change the behavior ?
Thanks again.
- raj
"Priscilla Oppenheimer" [EMAIL PROTECTED] wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
At 05:35 PM 2/10/01, Raj Singh wrote:
NOTE: Long email / question ... regarding ARP and Proxy ARP behavior with
different vendors OS.
A inquiry about ARP behavior, vendors, and differences.
Does the way a host machine behave during the ARP process differ amongst
different OS manufacturers, in relationship to when Proxy ARP can be
implement and when it can't be.
Yes. You would have to do some testing to determine which ones ARP for
non-local stations and which don't. (It sounds like you already did some
testing.) When I used to teach the CIT class, one of the "bugs" we
inserted
was to remove the default gateway in the PC. The goal was to make it
impossible for the PC to reach non-local stations. We also had to insert
"no proxy arp" in the router config, because sometimes removing the
default
gateway didn't cause a problem. We were at the mercy of whatever TCP/IP
implementation happened to be on the PC. Different vendors, different OSs,
different versions worked differently.
One other trick is to set the default gateway to the station's own
address.
For some strange reason, on some OSs this causes the station to ARP for
non-local addresses.
Priscilla
This inquiry should not be mistaken with "is proxy ARP a good idea or bad
idea" question. I just want to find some behavior facts out. Thanks.
Given the following situation:
ClientA ClientB
| |
||
|
|
X
{ROUTER}
Y
|
|
|-|
|
ClientC
Settings:
ClientA: 192.168.12.5 /24
ClientB: 192.168.12.6 /24
ClientC: 192.168.20.101 /24
Interface X on Router: 192.168.12.1 /24
Interface Y on Router: 192.168.20.1 /24
Proxy ARP enabled on both router interfaces
None of the clients have been configured with a default gateway setting.
The operating systems are Windows 98. (Though if you prefer you can say
it
is NT 4.0)
The basic statement that I have a question about:
According to Jeff Doyle's Routing TCP/IP vol. 1, book on page 69-70 in
quotes below -
"... For example, a host 192.168.12.5/24 needs to send a packet to
192.168.20.101/24, but is not configured with default gateway information
and therefore does no know how to reach a router. It may issue an ARP
request for 192.168.20.101; the local router, receiving the request and
knowing how to reach network 192.168.20.0, will issue an ARP reply with
it's
own data link identifier in the hardware address field. In effect, the
router has tricked the local host into thinking that the router's
interface
is the interface of 192.168.20.101. All packets destined for that address
will be send to the router. ..."
The question itself:
The question I have with this is that under a Windows environment at
least
in my experience, The decision making process is as follows when trying
to d
o an address resolution (ARP Request).
Sender looks at it's own IP address and Subnet Mask compares it to the
target machines IP address to determine if on the same subnetwork. If it
is
so . an ARP request is issued. But if the Sender's IP address and the
Target
's IP address are not part of the same subnetwork . the sending machine
looks for it's default gateway and does an ARP request for it.
Thus the problem is . if there is no default gateway setup for the sender
.
It won't even attempt to do an ARP request . it will IMMEDIATELY say .
Destination host unreachable.
Demonstration 1:
ClientA: 192.168.12.5 /24 PINGSClientC: 192.168.20.101 /24
Notice in the PING results below, where Client A pinging Client C, with
the
start and end time there is only a 6/100ths of a second difference from
the
start of the ping statement to it informing us no can do. Also note with
a
sniffer on the line there are no packets generated either from the
pinging
machine.
Current time is 4:25:34.81p -- Start Time
Pinging 192.168.20.101 with 32 bytes of data:
Destination host unreachable.
Destination host unreachable.
Destination host unreachable.
Destination host unreachable.
Ping statistics for 192.168.20.101:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms
Current time is 4:25:34.87p -- End Time
--
Demonstration 2:
ClientA: 192.168.12.5 /24 PINGS192.168.12.88 (non-existent
client)
Re: Silly Question!
It stands for "Internetwork Operating System" A little blurb from Cisco's web site: http://www.cisco.com/warp/public/732/ciscoios.html - raj ""Pierre-Alex"" [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... Do you know that the letters in "IOS" stand for? (Like in Cisco IOS 12.0) Pierre-Alex -Original Message- From: Dale Cunningham [mailto:[EMAIL PROTECTED]] Sent: Thursday, February 08, 2001 7:29 AM To: [EMAIL PROTECTED] Subject: Fwd: failure notice Pierre This came back into my mailbox this morning. Dale - Forwarded Message - DATE: 5 Feb 2001 11:27:55 - From: MAILER-DAEMON To: [EMAIL PROTECTED] Hi. This is the mailer-daemon. I'm afraid I wasn't able to deliver your message to the following addresses. This is a permanent error; I've given up. Sorry it didn't work out. [EMAIL PROTECTED]: CNAME lookup failed temporarily. (#4.4.3) I'm not going to try again; this message has been in the queue too long. --- Below this line is a copy of the message. Return-Path: [EMAIL PROTECTED] Received: from Unknown/Local ([?.?.?.?]) by mailcity.com; Fri Feb 2 20:37:25 2001 To: "Pierre-Alex" [EMAIL PROTECTED] Date: Fri, 02 Feb 2001 22:37:25 -0600 From: "Dale Cunningham" [EMAIL PROTECTED] Message-ID: [EMAIL PROTECTED] Mime-Version: 1.0 X-Sent-Mail: off Reply-To: [EMAIL PROTECTED] X-Mailer: MailCity Service Subject: Re: X-Sender-Ip: 208.50.127.100 Organization: Lycos Mail (http://mail.lycos.com:80) Content-Type: text/plain; charset=us-ascii Content-Language: en Content-Length: 880 Content-Transfer-Encoding: 7bit Pierre I think what they are trying to say is that by using vlsms you are getting as much efficiency as possible out of the addressing scheme (using a .252 for instance) so that using multipoint does not gain you anything. After all, you still have to have a seperate address within the subnet for each circuit. A .248 has six useable hosts, using multipoint with it would not gain you much. I would prefer to use point-to-point and use a /30 mask. Dale -- On Fri, 2 Feb 2001 09:27:47 Pierre-Alex wrote: On page 14-28 (ICND) It says: "Multipoint may not save you addresses if you are using VLSMs" What is the rational behind this statement. I would think that using a long subnet mask (i.e. 255.255.255.248 ) would not waste any ip address! Get your small business started at Lycos Small Business at http://www.lycos.com/business/mail.html - End Forwarded Message - Get your small business started at Lycos Small Business at http://www.lycos.com/business/mail.html _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: BGP Tutorial--anyone know a good one?
Try Avi Freedman's: BGP 101 http://www.freedman.net/bigbgp.ppt and BGP 102 http://www.freedman.net/bgp102.ppt tutorials. Also you should look into the Internet Routing Architectures 2nd edition, by Sam Halabi. http://www.amazon.com/exec/obidos/ASIN/157870233X/qid=981739964/sr=1-1/ref=s c_b_1/107-3760323-1100541 - raj "Leonardo Silva - Tecnologia" [EMAIL PROTECTED] wrote in message F7E7BC12B620D4119FA300C00D009BA0025C1AE8@EXCHANGESVRSAO">news:F7E7BC12B620D4119FA300C00D009BA0025C1AE8@EXCHANGESVRSAO... Hello! I'm looking for a BGP tutorial. If anyone know one it will help a lot. Tks. Leonardo Silva _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Silly Question!
Pierre, If you want to pick up more details on IOS, you might want to check out the Inside Cisco IOS Software Architecture book by Cisco Press. http://www.amazon.com/exec/obidos/ASIN/1578701813/o/qid=981751557/sr=8-1/ref =aps_sr_b_1_1/107-3760323-1100541 - raj -- ""Pierre-Alex"" [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... This is a great URL. Thanks! Pierre-Alex -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Raj Singh Sent: Friday, February 09, 2001 11:33 AM To: [EMAIL PROTECTED] Subject: Re: Silly Question! It stands for "Internetwork Operating System" A little blurb from Cisco's web site: http://www.cisco.com/warp/public/732/ciscoios.html - raj ""Pierre-Alex"" [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... Do you know that the letters in "IOS" stand for? (Like in Cisco IOS 12.0) Pierre-Alex -Original Message- From: Dale Cunningham [mailto:[EMAIL PROTECTED]] Sent: Thursday, February 08, 2001 7:29 AM To: [EMAIL PROTECTED] Subject: Fwd: failure notice Pierre This came back into my mailbox this morning. Dale - Forwarded Message - DATE: 5 Feb 2001 11:27:55 - From: MAILER-DAEMON To: [EMAIL PROTECTED] Hi. This is the mailer-daemon. I'm afraid I wasn't able to deliver your message to the following addresses. This is a permanent error; I've given up. Sorry it didn't work out. [EMAIL PROTECTED]: CNAME lookup failed temporarily. (#4.4.3) I'm not going to try again; this message has been in the queue too long. --- Below this line is a copy of the message. Return-Path: [EMAIL PROTECTED] Received: from Unknown/Local ([?.?.?.?]) by mailcity.com; Fri Feb 2 20:37:25 2001 To: "Pierre-Alex" [EMAIL PROTECTED] Date: Fri, 02 Feb 2001 22:37:25 -0600 From: "Dale Cunningham" [EMAIL PROTECTED] Message-ID: [EMAIL PROTECTED] Mime-Version: 1.0 X-Sent-Mail: off Reply-To: [EMAIL PROTECTED] X-Mailer: MailCity Service Subject: Re: X-Sender-Ip: 208.50.127.100 Organization: Lycos Mail (http://mail.lycos.com:80) Content-Type: text/plain; charset=us-ascii Content-Language: en Content-Length: 880 Content-Transfer-Encoding: 7bit Pierre I think what they are trying to say is that by using vlsms you are getting as much efficiency as possible out of the addressing scheme (using a .252 for instance) so that using multipoint does not gain you anything. After all, you still have to have a seperate address within the subnet for each circuit. A .248 has six useable hosts, using multipoint with it would not gain you much. I would prefer to use point-to-point and use a /30 mask. Dale -- On Fri, 2 Feb 2001 09:27:47 Pierre-Alex wrote: On page 14-28 (ICND) It says: "Multipoint may not save you addresses if you are using VLSMs" What is the rational behind this statement. I would think that using a long subnet mask (i.e. 255.255.255.248 ) would not waste any ip address! Get your small business started at Lycos Small Business at http://www.lycos.com/business/mail.html - End Forwarded Message - Get your small business started at Lycos Small Business at http://www.lycos.com/business/mail.html _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Nortel VPN books?
Hey Mark, Try the Nortel web site. www.nortelnetworking.com VPN Document Library - http://www.nortelnetworks.com/products/01/ip_vpn/doclib.html Also check these books out and see if they have any VPN sections specific to Nortel (Don't buy them unless you check them out first at a local bookstore - MicroCenter in Philly / Main Line area would be good for you.) - Nortel Networks: The Complete Reference by James Knapp: Osborne Pub; ISBN: 0072120274 - Nortel Networks Router Configuration by Jean-Pierre Comeau: McGraw-Hill Professional Publishing; ISBN: 0072125330 - Nortel Networks Troubleshooting and Optimization by Ragho Mahalingam: McGraw-Hill Professional Publishing; ISBN: 007212654X - raj -- [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... Hey group, Anybody know of ANY Nortel VPN books out there? I Decided to go with Berkowitz's book for VPN in general but found out that I'm going to need to know about Nortel VPN's. Haven't seen any books out there. Will I have to go to training or does somebody know of a book? Thanks for the input. Mark Z... _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
