3,901 reputation
916
bio website
location London, United Kingdom
age 43
visits member for 5 years, 2 months
seen Aug 5 at 11:13
Quite boring, really. Have faffed about with computers since the mid-80s, have worked as a network engineer, unix sysadmin and (occasionally) developer.

Jul
1
comment Cisco ACL Not Applying
You can certainly apply a single ACL both in- and out-bound. I have done it multiple times. Admittedly prima=rily for "tracking" ACLs (with specific "ip permit" statements for what I am interested in, finishing with a blanket "ip permit any any")
Jun
17
comment Isolating one router port from the rest
By default, the router will happily route traffic between A,B on one side and C on the other. However, broadcast traffic will not pass between the two VLANs.
Jun
15
comment How to tell if a router traffic shapes?
They may modify the TOS/DSCP bits in the IP header and they will ALWAYS modify the TTL. They shouldn't be touching the payload, though (except, possibly, splitting it if teh packet needs to be fragmented and the DF bit isn't set).
Jun
15
comment Is there a general guideline to setting up Firewall policies for Small Business?
It's easier to allow things you know are necessary than to block things you know are bad. Lessens the administrative burden (apart from the initial set-up, but that's painful anyway) and increases security. Since this is, essentially, @uSlackr's answer, I just voted it up, instead of writing a new, duplicate answer.
May
25
comment Cisco 3750 - EIGRP not on common subnet problen
Check the ARP table, should have an entry for 10.13.1.251. Then use (if you have Cisco switches...) "show mac-address-table address <MAC address>" to track it from switch to switch.
May
16
comment How to revoke a certificate?
Seems like this user has posted quite a few homework-looking questions recently. As a general rule, show us what you have tried so far. Rephrasing the question is a good start, though...
Mar
8
comment Public IPs on MPLS Traceroute
@vivek: No worries, if I thought it was a waste of my time, I probably would just have ignored it. As-is, I hope I have given some clarity and guidance.
Mar
7
comment Public IPs on MPLS Traceroute
@vivek: HSRP normally requires that the two devices share a broadcast domain, this will (probably) be true on the customer LAN side, but not on the WAN sode, so you would need to have dynamic routing enabled as well. Best thing to do is probably to discuss the proposed design(s) with your ISP(s) and they should be able to advise on the specifics.
Mar
7
comment Public IPs on MPLS Traceroute
@vivek, a hesitant "maybe". You can extend an MPLS VRF over multiple VLANs, if the underlying transport supports VLAN tags. As long as you can have independent L3 routing between the sites, you can do routing-based failover. The main win between having MPLS in the SP backbone versus not having MPLS is that your IP space is isolated from that of other customers of the SP, but that is the case no matter if the MPLS terminates on the PE or the CE.
Mar
7
comment Public IPs on MPLS Traceroute
@vivek It all depends on how the service provider has built the network and what service the customer needs. If all the customer needs is a "single pipe", having a customer edge device that speaks just plain IP with the provider edge means less traffic (probably not by much, but at least by one, probably two MPLS tags) and the possibility of using cheaper CE devices (as they'd only need to speak IP instead of MPLS). It also makes it possible to let the customer own/manage the CE device, something that is inadvisable if you're exposing your LDP to them.
Mar
7
comment Sharing connections on a circuit-switched network possible?
ATM and Frame Relay is, typically, circuit-switched (well, it's arguable that they're label-switched, but...). MPLS is pretty close to being circuit-swicthed.
Mar
7
comment cisco 6500 crash enabling netflow
Alternatively, talk to whoever you have a service contract with and have them open a TAC case for you.
Feb
24
comment getting cisco on the net
Do you have NAT set up? Your DSL gateway will, probably, only allow NATing for a 192.168.1.0/24, so you will need to NAT yout 100.0.0.0/8 netblock into that (then to get NATed again, as it egresses through your DSL router). I'd also consider changing the 100/8 network to a /16 out of 172.16/12
Feb
17
comment Any thoughts on 6 inch ethernet patch cables?
I don't believe there's a spec for minimum distance in the xBase-T standards, but there is a practical shortest limit that depends on the equipment. There are minimum distances between taps on 10Base-5 and I believe there is a minimum distance between T-connectors in 10Base-2. However, I doubt those are frequently deployed, these days (and I suspect most legacy installatiopns have been converted by now).
Feb
10
comment Need reasonably priced router with QoS support
Unless you're doing connection-tracking (like, say, NAT), the number of simultaneous TCP connections is pretty much a non-issue. What aggregate bandwidth are you expecting?
Jan
25
comment What are your best senior level Linux interview questions
It at least used to be the case that editing config files in AIX did not result in daemons changing behaviour, as they picked up the config from a binary database, instead of the plain-text config file.
Jan
24
comment Looking for a network tester that can measure the speed of one cable
@Martin: In that case, I suspect Fluke have one or more suitable devices in the USD 1000+ cost range
Jan
15
comment Basic multicast network performance problems
Might be. Might be worth testing, to see if it is that that's killing your CPU (probably out of hours, though). Can't say I've seen it in the 4900, but I have certainly seen packet-loss due to te presence of IGMP snooping on 4ESW ports.
Jan
13
comment Basic multicast network performance problems
Might be worth disabling IGMP snooping, I've seen issues due to that on other platforms (though that was packet loss rather than latency).
Jan
10
comment BVI vs Bridge routers
@George Bailey: The ability for the router to interact with the interfaces on a Layer 3 level (or, as far as I recall at least). The "BVI interface" is, essentially, the same as the "Interface VLAN" on a switch (the SVI).