Someone told me that before going to be a network administrator you must be good at system administration is it true? please guide me i have planned to make career in networking.

erm no. I would suggest the opposite is more true. If you are a sysadmin who hasn't got a clue what's happening past your NIC, you're going to do a bad job. Other way round, it's much less critical.

Did you have any examples of why sysadmin knowledge helps? That's GOT to be OS agnostic by definition, so isn't able to go too far down the stack.

The only grey area that springs to mind is something like how FTP works, with it's archaic port operations, but again that's something a sysadmin is less likely to know that a netadmin.

As a network Engineer you often have to troubleshoot networking issues that affect hosts. However if the organization has System Administrators you're not going to be allowed to access the hosts directly.

Having said that however most switches, firewalls and other networking appliances you might deal with (e.g. F5 BigIP) do have operating systems of their own on them and you'll likely need to know those well. Many of these are either embedded Linux or something that looks and acts a lot like Linux. Since these are almost always customized though general Systems Administration won't necessarily help you more than learning the specific administration for those devices.

All in all I'd disagree with the statement you heard but will say that knowing System Administration likely would be helpful in learning the other stuff. Many commands used in UNIX/Linux such as tcpdump, netstat, netcat etc... are also available on networking devices or are needed to externally monitor things.

@acid_kewpie -- how could one understand networking concepts without knowing enough system concepts. as far as my reading goes, the first three layers of a IP protocol stack gets implemented in a software so I think and believe that knowing and understanding systems comes first then comes a network.

@MensaWater -- which one of these two fields, networking and sysadministration is more chanllenging and demanding.

---------- Post added 12-19-12 at 01:44 PM ----------

@acid_kewpie -- how could one understand networking concepts without knowing enough system concepts. as far as my reading goes, the first three layers of a IP protocol stack gets implemented in a software so I think and believe that knowing and understanding systems comes first then comes a network.

@MensaWater -- which one of these two fields, networking and sysadministration is more chanllenging and demanding.

Can you provide an example?

As I commented on above, FTP is the best example I can think of, but I learned about FTP data flows when I did my CCNA, not RHCE.

Sure parts of the stack are done in software, but they're coded to existing RFC's that are also implemented in network devices, and are really only knowledge for network admins. As much as you have read something that has stuck in your mind, if you can't provide any examples, I don't see how you can defend this position.

In terms of what is more challenging, it really depends how deep you want to go into it. Network administration is potentially broader, and more theoretical at times. You could get a CCIE one day and be designing international MPLS / BGP WANs. Sysadmin, when based within it's own confines, is generally much more likely to be a simpler thing, dealing with more things in a day, but each tending more towards the simple side of theory. At the other end of the spectrum though, neither a network admin plugging cables into switches and a sysadmin rebooting windows boxes require much intellect or cross tech knowledge.

I'm a system admin rather than a network engineer and I find it challenging and demanding enough for a host (pun intended) of reasons. However looking at it from the outside it seems to me that Networking is probably more demanding and challenging. With systems you might take out key functions important to the entire organization by accident but you're usually going to be troubleshooting the actual issue on a single system (or cluster at worst) whereas with networking you can take out the entire organization by simply having things be globally inaccessible.

Both roles suffer a common issue: What you do sits below much of what everyone else does and people are apt to blame the lowest common denominator rather than troubleshooting their own area. Since networking sits below systems Network Engineers probably get more of this from Sys Admins whereas Sys Admins get more of this from Application/Database folks but the latter are just as apt to blame networking as the OS.