From: Joe Gagznos (joeandkt@idcomm.com)
Date: Wed Apr 06 2005 - 11:06:57 GMT-3
Congratulations, Jongsoo! Nice to hear this thing can be beaten. Time for
some well deserved rest!
Joe
Jongsoo kim writes:
> Dera All
> I failed last 28-Feb in RTP and when leaving the RTP, I felt very
> positively I might have a good chance to pass it ...but yesterday when I was
> leaving RTP, I knew I finished all the questions on the paper with a
> confidence that this should be the answer because there is no other ways or
> I am 100% compliant to the restriction... On the other side, if I failed, I
> will definitely ask for regrading...
> However, I also had a feeling what I am going to do if I failed this time
> after that much of study...
> Obviously, the confidence that I used to have when I knew only a couple of
> ways to make it work isn't with me after I learned so many other ways that I
> didn't know...
> Anyway, let me go over how our check list worked during my lab.
> First, I followed it exactly. CAT table, IGP drawing, and BGP drawing. Each
> of these drawings capture everything but IP address. IGP Darwin has a nice
> coloring per protocol (well-sharped pencil was really good to use).
> I was like MLS switch as only first packet of a new flow go through process
> and all other done by ASIC.
> Anything missing, I just update my drawing so that I don't have go through
> again multiple papers, which reduced significantly my brain CPU cycles.
> I finished L2, IGP, ISDN, and BGP ( with 4 questions( route filters)
> skipped, unrelated to full reachability) with TCL scrip validation of a good
> working full reachability before lunch. I couldn't believe how fast I was
> able to finish OSPF compared to last time. I rebooted router right before
> lunch. When I came back, I ran again TCL and surprised to find out ping
> failed to one router and BGP neighbor down. One of default-metric
> disappeared...which I thought might happen to my other trials..
> After I achieve a full reachability by lunch, I knew I am controlling time
> unlike being controlled by it in my last attempt.
> It was a totally different game when I can control the time...
> Whenever I do some flow restriction, I ran TCL to validate I am not breaking
> any previous works.
> There was only one question( 2 point) I didn't know...ironically it was the
> last question of the lab and it was security again related to some flow
> restriction...Initially I thought it is only 2 point and I'd rather give
> this up because I didn't want to repeat my nightmare on my 2nd attempt. But
> I sort of recalled some discussion on groupstudy on similar topic. After
> some research on CD, I was able to get it right because my solution matched
> the result criteria. Immediately, I ran TCL script and check all the related
> protocol.
> And finally, I rebooted all the routers and Sw of course after "wr" before
> going to restroom.
> And I ran again TCL and saw ping drop but I was in a good control because I
> was confident my config is correct.
> It turned out that SW OSPF came up later than router...
> That was the last thing I did. and I walked out...
> Regards
> Jongsoo
>
> On Apr 4, 2005 2:25 AM, Jongsoo kim <bstrt2002@gmail.com> wrote:
>>
>> Folks Thanks for all the excellent feedback .
>>
>> Based on group's feedback and my trial test to see how pratical and
>> efficient my check list,
>> I revised some of them. Also I was advised that I can't bring the outside
>> pens so that I will do coloring with those color pencil available on desk.
>>
>> #1 Spend a few minute to understand the point distribution between
>> Core requirement (L2, IGP, BGP, ISDN) and non-core ( IOS, Service,
>> Security, Mcast)
>>
>> #2 Spend a few minute to understand the topology.
>> Figure out core network, stub network, BB
>>
>> #3 Enter Alias command to notepad and copy paste all router.
>> "show run | b Se" ( surprizingly, I didn't use this command after I build
>> drawing because I can find out my sub-interface number from drawing!
>>
>> #3 Attack F/R ( targetting 10~15 min)
>> While reading the task,, Draw a quick diagram showing interface type ( ph,
>> m, p2p).
>> Configure Router by router not interface by interface
>> Always 0) shut 1) enc frame-remay 2) no frame inverse 3) no shut.
>> Ping from spoke to spoke if possible. to vaildate.
>> If PPP over FR, then always create VT first, user/password
>> In this way, I was able to do this in 7 min for 3 pvc's ( each pvc has
>> different interface type).
>>
>> #4 Attack CAT ( 25~35 min)
>> 4-1While reading the task, make VLAN table like below
>> VL Router CAT1 CAT2 Router VL
>> 10 R1 f0/0------f0/1 f0/2 ---------f0/0 R2 10
>> 20 R3 f0/1------f0/3 f0/4 ---------f0/0 R4 30
>> 40 R5 f0/0 ------f0/5
>> 40 R6 f0/1-------f0/6
>> f0/23---f0/23
>> f0/24---f0/24
>> vl 10 vl40
>> client vtp server vtp
>> Determine VTP mode, trunk mode.
>> 4-2 Delete vlan data base " delete flash:vlan" before configuring !
>> Then configue 1) VTP, 2) Vlan, 3) cat-cat 4) access port, 4) trunk port
>> 4-3 Read task once again and make sure nothing missed
>> 4-4 ping vlan by vlan. Select only one device and ping all other on a
>> specific vlan.
>> > No need to ping from multiple interface on a same vlan.
>> > Don't wait for Arp resolution!
>> CAT takes about 25 minutes in my scenario ( but real lab would take
>> shorter)
>>
>> >
>> > #5 Attack ATM ( I can spend a lot time if I screwed config. 5~25min )
>> > Quickly decide PVC vs SVC
>> > 5-1 If SVC, then decide "CLIP" or "SVC nsap"
>> > Put "pvc 0/16 ilmi and pvc 0/5 qsaal " and "show atm ilmi-status" to
>> > vaildate nsap address.
>> > 5-1-1 if CLIP, then decide "arp-server self" or "arp-server nsap"
>> > And then decide physical or sub
>> > 5-1-2 if SVC nsap, decide physical or logical
>> > 5-2 if PVC, then decide "pvc vci/vpi" or map-list/map-group
>> > 5-3 after 5-1 or 5-2 done, figure our nsap or vci/vpi. Pay attention
>> > nssp is HEX!
>> If PPP over ATM, then always create VT or dialer interface first, then
>> > user/password
>> > 5-4 ping and validate
>>
>> ############## L2 is over between 40~1:15
>> ###########################################
>> >
>> > #6 Attack OSPF
>> Based on my test, it was very important the way I write down on paper in
>> order to make router-by-router step work.
>> 6-1 While reading the task, Draw a diagram to configure OSPF router by
>> router not area by area w/ green coloring.( 10 min)
>> > Check if there are
>> > authentication
>> > stub or nssa.
>> > virtual link
>> > Make a note on redistribute, summary, area-range.
>> > Pay attention DR/BDR, OPSF network type
>>
>> Write config separately for interface and ospf on drawing.
>> For example, the below was my note on drawing I made while I am reading
>> task.
>>
>> For R1
>> int s0/0.123
>> p2m, md5,
>> int s0/0.14
>> non-bro, pri 0, md5
>> int f0/0
>> nothing
>>
>> ospf
>> r-id
>> a 0 md5
>> a 12 nssa no-sum, no-red
>> a 13 stub no-sum
>> a 12 v r4 md5
>> a 14 v r2 md5
>> a 5 v r3 md5
>> nei R2
>> neii R3
>> area 5 range
>> summary
>>
>> This method makes configuration time very short but it was extremely
>> important to not forget anything to configure router-by-router as many
>> people pointed out.
>>
>> > 6-2 Configure OSPF router by router based on drawing in Black ( 10~30
>> min)
>> First Interface and then router ospf
>> > 6-2-1 Preferred sequence for configuring interface was 1)OPSF network
>> type based, 2) priority, 3) Authentication,
>> > 6-2-2 Preferred sequence for configuring OSPF process was from
>> "easy-to-forget" to "always know" 1) router-id( it seem to only help for
>> Virtual-link, I will skip if there is no Virtual link ) 2) area
>> authentication, 3) area virtual link, 4) neighbor, 5) Network (copy past
>> from interface address)
>> > 6-2-3 Validate everything is working( show ip os ne, show ip os vir,
>> show ip os interface, show ip route ), ( 5 min)
>>
>> Just a note wth this method, I was able to do OSPF among five routers in
>> 15 min from drawing to core config not including redistribute/summary/area
>> range. This is my record time.
>> Specially, virtual link config really seems to save time.
>> There isn't much of trap in OSPF like Rip. very easy to validate it as
>> well. If config work, in most case it should be correct...
>>
>> 6-3 Do redistribute, summary, area range ( 5 min)
>> It was necessary to separately treat area range, or summary
>>
>> 6-4 avoid any engagement with giant beasts. But make a note.
>>
>> #####OSPF is from 35 ~ 55 Min ( total 1:15 ~2:10)#######
>>
>> > 7 Attack RIP( 20~30 min)
>> > It is very tricky!
>> > 7-1 add RIP topology into OPSF drawing with blue coloring( 2 min).
>> It seems Rip doesn't really have much detail info on drawing.
>> > 7-2 Make sure active/passive interface
>> WATCH OUT Split-Horizon is off on pfysical FR and ATM !
>> > Pay attention of rip update method ( M/B/U) and version, authentication
>> > Never assume it is always V2!, no auto-summary, mcast, etc
>> > This selection can be applied to each direction of interface.
>> > 7-3 Configure router by router( 5 min) per drawing
>> In fact, core rip configuration is always router by router as rip doesn't
>> have concept of adjacency per link.
>> > 7-4 valiadte ( 3 min)
>> > 7-5 Spend enough time to be absolutely correct on route-filter,
>> > summary, etc ( 5 min)
>> > 7-6 If mutual-redistribution is required, make sure multi-exit point
>> > ot single-exit point. Don't fotget metric.
>> > If it is multi-exit point, write down "rip subnets" on notepad and do
>> > the following( 5 min)
>> > 7-6-1 "redistribute ospf" under "router rip"
>> > ##### Provent Rip-originated routes entering Rip from OSPF ############
>> > "Deny rip routes and permit all" route-map for "redistribute ospf" to
>> rip
>> > Don't wait after "clear ip route * " is issued if I am not "idiot!"
>> >
>> > 7-6-2 "redistribute rip subnets" under "router ospf"
>> > ##### Provent OSPF external routes entering OSPF from Rip #####
>> > "Permit only rip routes" route-map for "redistribute rip subnets" to
>> OSPF
>> > Don't wait after "clear ip route * " is issued if I am not "idiot!"
>> >
>> > 7-6-3 distance 121 0.0.0.0 <http://0.0.0.0/>
> 255.255.255.255<http://255.255.255.255/>11 under "router OSPF"
>> > ##### Fix redistributing router's AD for Rip routes #####
>> > distance 121 0.0.0.0 <http://0.0.0.0/>
> 255.255.255.255<http://255.255.255.255/>11
>> > "access-list 11 permit rip routes"
>> > I saw sometimes this takes quite a few second. Don't do "clear ip
>> > OPSF" or I will end up spending more time just for watching.
>> >
>> #### RIP is over 20 ~30 min( total 1:35 ~ 2:40) ############
>> >
>> > 8 Attack EIGRP ( 20~30min)
>> > 8-1 While reading the task, add EIGRP topology into OPSF drawing in
>> black w/o blue coloring ( 2 min).
>> > 8-2 Determine non/passive/active-eigrp interface. Be open minded that
>> WATCH OUT Split-Horizon is off on pfysical FR and ATM !
>> > BB can be multicast/unicast. Load-balance, authentication, stub,
>> > summary address( 5 min )
>> > 8-3 Configure router by router( 5 min) per drawing
>> > 8-4 validate ( 5 min)
>> > 8-5 Spend enough time to be absolutely correct on route-filter,
>> > summary, etc ( 5 min)
>> > 8-6 If mutual-redistribution is required, make sure multi-exit point
>> > ot single-exit point.
>> >
>> > If it is multi-exit point, write down "eigrp subnets" on notepad ( 5
>> min)
>> > 8-6-1"redistribute ospf" under "router eigrp"
>> > #####Protect EIGRP external route reentering from OSPF #######
>> > "Deny eigrp routes and permit all" route-map for "redistribute ospf" to
>> eigrp
>> > Make sure metric is configured.
>> >
>> > 8-6-2 "redistribute eigrp subnet" under "router ospf"
>> > ##### Protect OSPF external routes reentering from EIGRP
>> > "Only permit eigrp routes" route-map for "redistribute ospf" to eigrp
>> > Make sure metric is configured.
>> >
>> > 8-6-3 distance 121 0.0.0.0 <http://0.0.0.0/>
> 255.255.255.255<http://255.255.255.255/>11 under "router OSPF"
>> > ##### Fix redistributing router's AD for eigrp external routes #####
>> > distance 121 0.0.0.0 <http://0.0.0.0/>
> 255.255.255.255<http://255.255.255.255/>11
>> > "access-list 11 permit eigrp routes"
>> > I saw sometimes this takes quite a few second. Don't do "clear ip
>> > OPSF" or I will end up spending more time just for watching.
>> > Technically, only eigrp external route needs to be applied but eigrp
>> > route won't hurt and make it simple.
>> >
>> ######EIGRP is over in 20~30 min (1:55 ~3:10 min) ##############
>> >
>> > 9.Attack ISIS ( 10 min)
>> > 9-1 While reading the task, add ISIS topology into OPSF drawing in black
>> w/ purple coloring ( 1 min).
>> > 9-2 determine area type, IS-type, authentication ( domain, area,
>> > interface level1-2).
>> > Make sure of correct value of NET ( it is Hex), summary address
>> > 9-3 Configure router by router.
>> > 9-4 I don't believe there will be multi-exit mutual redistribution on
>> ISIS
>> > Make sure to redistribute connect network from ISIS to OSPF.
>> >
>> ###### ISIS is over in 10~15 min ( 2:05 ~3:25)
>> >
>> > 10 Attack ISDN ( 15~30 min)
>> > 10-1 draw ISDN on a separate paper. ( 30 sec)
>> > 10-2 Determine single/both callers, authentication type( no
>> > auth/pap/chap), physical/dialer interface. PPP feature = multilink,
>> > callback,
>> > 10-3 Figure out back-up method ( floating static/OSPF demand/watch
>> > group/back-up interface/rip trriger/ snap-shot routing ) focus on how
>> > full reachability can be accomplished after F/R failed. Make sure
>> > link is not flapping.
>> > 10-4 Determine if there is additional task for interesting traffic
>> filtering.
>> > 10-5 configure ISDN router by router.
>> > 10-5-1 select switch type, spid and shut and no shut and show isdn
>> status.
>> > make sure L2 is happy! Also make a quick test call using both
>> > string " isdn test call interface bri0/0 "string" " and disconnect "
>> > isdn test disconnect interface bri0/0 all"
>> > 10-5-2 validate the link
>> >
>> ###### ISDN is over in 15 ~30 min ( 2:20 ~ 3:55)
>> >
>> > 11 Golden Moment ( 5~30 min)
>> 11.1 Test full reachability with ISDN back-up link off
>> > Check the Golden moment per NMC meaning the exciting moment when you
>> > get ping response from every router to every router.
>> > Run tclsh script
>> > "foreach addr {
>> > 1.1.1.1 <http://1.1.1.1/>
>> > ...
>> > } { ping $ addr}"
>> > Just copy past after tclsh ( it is really cool when you see pings go
>> > through from everywhere to everywhere). To quit, juts type " tclq"
>>
>> 11.1 Test full reachability with ISDN back-up link on
>> 11.2 when ping has no response, write down ip address and troubleshoot.
>> > Drawing will be the excellent tool for troubleshooting
>> > Don't bother ISDN link yet.
>> >
>> ########### Full reachability is done in 5 ~30 min ( 2:25 ~4:25)
>>
>> > 12 Attack BGP( 20 ~40 min)
>> > 12.1 While reading task, Drawing a BGP topology on a separate paper.( 3
>> min)
>> Drawing is very imnportant in BGP
>> 12.2 Determine RR or CON or both to do full-mesh iBGP.
>> > See if neighbor peer-group is required,
>> > decide ip address ot use bgp session.
>> > 12.3 Configure router by router not BGP session-by-session
>> > always put no sync and no auto-summary if allowed.
>> > 12-4 Spend enough time to be absolutely correct on route-filtering (
>> > ACL, prefix-list, as-path filer), route-aggregate(w/ as-set,
>> > summary-only, supress-map, attribute-map, advertise-map),
>> > route-manipulation( w/as-prepending, med, local-pref, weight,
>> > next-hop, advertise-map/non/existing-map, orgin, community, etc )
>> > route-dampening, etc.
>> > 12-5 vaildate config. Use "clear ip bgp * soft " not " clear ip bgp *
>> and I don't have to wait!
>> >
>> ###### BGP is over in 20 ~40 ( 2:45 ~ 5:05) My target is before lunch!
>> >
>> > 13 IPv6( 10 min)
>> > 13-1 draw a sipmple diagram ( 1 min)
>> > 13-2 Watch out link local address over FR multilink.
>> > SLA ID is 4th 16bit
>> > 16bit:16bit:16bit:SLA ID(16 bit) : interface ID( 64 bits)
>> > site-local = FEC0::
>> > link-local = fe80::
>> > 13-3 Check a full reachability using tcl script or just manual ping
>> > depneding on the number router.
>> >
>> > IPv6 is over 10 min ( total 2:45 ~ 5:15)
>> >
>> > ################## Core routing is done ####################
>> > I should have at least 2:45 hours to go at least.
>> >
>> > Strategy will change depending how much time I have at this moment.
>> >
>> > 14 I would do multicast first ( 15 min)
>> > 14-1 While reading task, mark a Mcast topology with red high lighter on
>> OSPF drawing.
>> > 14-2 Determine mcast topology ( dense-mode, static RP pim sparse,
>> > Auto-rp/MA, pim V2 bsr, Auto-rp/MA/MSDP).
>> Spot any RFP issue per IGP topology
>> > 14-3 Configure router-by-router
>> > 14-4 valildate it
>> > 14-5 If second part is difficult, skip by making a note.
>> #####Minimum 2:30 left
>> > 15 IOS/IP service ( 25 min)
>> > Be careful not to block or drop any IGP updates
>> > 15-1, just check quikcly and do easy one first.
>> > 15-2, skip difficult task by making a note
>> ###### minimum 2:05 left
>> > 16 QoS ( 30 ~ 40min)
>> > Be careful not to block or drop any IGP updates
>> > 16-1 Draw a flow on paper instead of in brain.
>> > 16-2 Always determine classification method( ACL, NBAR) and direction.
>> > 16-3 Determine shaping vs policing
>> > 16-4 Consider all options for queuing( legacy custom/priority,
>> > bandwidth/priority, shape average/peak, FRTS/GTS)
>> > 16-5 consider all options for policing ( police, rate-limit, ip
>> > multicast rate-limit, aggregate police( 3550))
>> > 16-6 If frame-relay, don't forget adaptive-shaping.( becn, fecn,
>> foresight)
>> > 16-7 Consider all droping mode (random detect, ecn, tail drop, marking,
>> etc)
>> ##### minimum 1:25
>> > 17 Security ( 30~40min)
>> > Be careful not to block or drop any IGP updates
>> > 17-1 Draw a flow on paper instead of in brain.
>> > 17-2 Consdier all options for classification
>> > std/ext/reflexive/dynamic ACL,
>> > IP insepct,
>> > tcp intercept
>> > unicast RFP,
>> > ip accouting output packet /access-violation/precedence,
>> > 17-2 When configuring Switchport port-security mac-address, be careful
>> > to include vurtual and physical mac if HSRP is running.
>> ###### minimum 45 min
>>
>> > 18 DLSW( 15 min)
>> > 18.1 Draw a qucik topology ( 1 min)
>> > 18.2 Decide method of DLSW TCP, fst, fr.( I think only TCP will show up)
>> > Peer on-demand( group/border)
>> > Dynamic peering ( dynamic)
>> > Loadbalance (round-robin, circuit-count),
>> > Back-up ( back-up peer or cost)
>> > DSLW use tcp 2065 and udp 2067
>> > NAT can affect DLSW ( higher ip DLSW peer drops)
>> > 18.3 decide type of filtering
>> > 18-3-1 Netbios name filter( netbios access-list host xyz permit zyx )
>> > Icanreach/icannotreach netbios-name /netbiosexclusive
>> >
>> > 18-3-2 MAC address filer ( access-list 700-799, mac-address conevrsion
>> needed )
>> > Icanreach/icannotreach mac-address/mac-exclusive( address conversion)
>> >
>> > 18-3-3 LSAP filter ( access-list 200-299 permit )
>> > SNA only "access-list 200 permit 0x0000 0x0d0d"
>> > SNA and Netbios " access-list 200 permit 0xf0f0 0x0101
>> > Icanreach/icannotreach saps
>> > icannotreach saps f0 ( deny netbios)
>> >
>> ###### minimum 30 min #############
>> I am planing at least 1:30 hour left.
>> I will do " tcl script " one more time to make sure everything work.
>> I expect 2 ~ 4 question I will skip.
>> At this moment, depending on how much time I have, I quckily go back to
>> the qeustion I skipped.
>> I will invest my time to something I can see best chance of getting right
>> out of the skipped ones.
>> Jongsoo from RTP
>
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