Printing in OS X
|
Our Day Has Come |
|
|
|
|
David Ross Explains IP Addresses and Routers This is a VERY VERY simplified overview of the issues that have come up here over the last few days. Plus Alfred Scott asked for help help and I realized that this can get very confusing very quickly. And if you think this is too simplified or some of my givens too strict, then you likely don't need to even read it. If you want to use IP for printing and don't have a router then Step 1 is to get a router. Otherwise your life will be complicated. The rest of this assumes a router between your office network and the outside Internet. IP addresses need subnet masks to tell them how to relate to each other. Devices on the same subnet can be thought of as being in the same working group. I'm going to assume that everyone's router is using a subnet mask of 255.255.255.0 on the LAN (your office) side of things. Look in your TCP/IP or networking control panel on one of your computers to see your settings. The subnet mask will be in there. If it's not 255.255.255.0 then you have more work to do than I'm going to go into here. With a subnet mask of 255.255.255.0, all the IP addresses in an office should be the same in the first three numbers. I.E. 192.168.1.5 and 192.168.1.88 are in the same subnet with the given mask. 192.168.4.5 is not. Each group of digits in an IP address can range from 0 to 255. Most office networks will have numbers that start with 192.168.x.x or maybe 10.x.x.x. If not you likely don't need to read this or need more help than is covered here. All IP addresses in your office need to be in the same SUBNET!!!!! While different subnets CAN talk if one the same hub/switch and everyone plays nice, this should be avoided unless you like to live in interesting times. There's an exception noted below. All non-routers should not use an ending number of .0, .1, .254, or .255. (I'm simplifying but do this unless you know the rules.) Everything in the office has to have a unique IP address. Your router may or may not be handing out IP addresses. If it is, the process is called DHCP (Dynamic Host Control Protocol). What happens is your turn on a computer, or printer, or whatever and it asks for an IP. Any available DHCP server, in general, will then hand one out. Most big box store routers do this out of the box. (LinkSys, Netgear, etc...) These are called Dynamic IP addresses. Most DHCP servers (built into most routers) will TRY and assign the same IP address to a device each time. It does this by using the device's MAC address which is unique (99.9999%) to every ethernet device on the planet and has nothing to do with Apple. (Isn't life confusing.) But unless your router supports it, and you take the time to set it up, this same IP every time isn't guaranteed. This is why most folks can get things working at first but a week or year later everthing quits and they don't know why. You may have devices on your internal network with static (fixed and non-changing) IP addresses. If so, you or someone set the IP address of the device in some way. You can mix dynamic and static IP's on a network and everyone will be happy as long as there's no duplication and all are on the same subnet. If you have a mix then for sanity you should set the address ranges apart from each other. I.E. something like set the static ones from the range of192.168.1.11 to 192.168.1.99 and the dynamic ones to be handed out starting at 192.168.1.100. Most routers these days have a web interface you can access to change things like this by putting the IP address of the router into a web browser. NOT the external IP address give out by your ISP, but the internal one shown in your Networking or TCP/IP control panels on one of your computers. Now about plotters and such. For IP printing they need an IP address. They also need a print server. HP calls their print servers JetDirect. HP has made a LOT of variations of these over the years. Plus you can buy print servers from LinkSys, Netgear, etc... These print servers need to get an IP address. Most newer ones can have a static IP set or can get one via DHCP. Some older ones get an IP using DHCP's ancestor called BootP. Newer ones have flash memory and can remember their settings even if the power is off for weeks at a time. Older ones are fairly primitive and depend on getting their settings every time. The beige HP Jet Direct boxes fall into the later category. Based on what's been said here about setting up print queues and such a non-changing IP for the print server seems best. So you likely want to either set it up as a static IP or set your DHCP server (usually a sub function in your router) to hand out the same IP address to the device each time. If you don't do one of these you may get to reset your print queue every now and then when (for a variety of reasons) your devices are handed a new IP address. If your Jet Direct is inside the plotter/printer then you likely can set the IP address to a static one via the front panel. It's a bit tedious, but it is doable and works just fine for these these types of Jet Direct cards. Alfred Scott had an old beige JetDirect EX, and it wasn't getting an IP address from his LinkSys router. I'm guessing it is due to the LinkSys not handling BootP. Given this, I'm going to suggest that folks with these older JetDirect boxes toss them and go get a newer model. I've installed three JetDirect 300X models with good success. It currently costs about $250 new and $100 on eBay. You'll also likely need to get a new cable. (All of mine have come from eBay.) These newer boxes, and most of the non-beige ones, allow you to Telnet (a line-oriented command setup) into them and set the various parameters. You can plug the Jet Direct up, reset it via the buttons, print the TWO configuration pages (8.5x11 or 11x17 paper is recommended over 24x36 because you will get two pages) via the button, then telnet into it via the IP address show, change the settings, save them, reprint to make sure they stuck, then you're done. To first telnet into the box, you need its current IP address which you printed. This is either assigned to it via DHCP or usually set to 192.0.0.192 on HP Jet Direct units. It doesn't matter if it's not on your subnet for this as you can telnet directly to the box as long as it's on your current network, and you don't have a lot of switches and hubs in the way. (KISS) Some units now support web browsing to set things. Just enter the IP address where the URL goes. You can do similar things with many of the 3rd party boxes but the details vary all over the map. Handy tools to have for OS 9.
And remember, your own setup might work without following the things I've said above. Either I've simplified things more than whoever setup your network, or you're fortunate. Many times things will work with a setting or two not exactly right. After all is done, you'd be well advised to make notes about your router, print servers, computers, IP addresses, etc... Six months later it can get real hard to remember all the details of what you did. David Ross Excellent description David. Thank You. I have my server set up to serve IP addresses. Should I let the router take care of this? Whatever works best for your office. If one or the other lets you tie the MAC address to the IP address then I'd go with that one. In general I've come to the conclusion that everything but computers should be done with static IP addresses. And doing the computer has benefits. More time up front, less time when you're tracking down a problem. Of course the first time I heard the phrase "like herding cats" was in relation to trying to deal with static IP addresses on 1000s of computers. (This was before the Superbowl commercial.) The break point is somewhere around 20 to 50 devices. After that you should look at investing in pro networking equipment. David Ross Well said David. I would add another thing though. I believe a local network should only have one DHCP device handing out IP addresses in any zone of the network. I mention this because some people may have an Airport network running which is set to be the DHCP server (and they may not know it). If they are going to introduce a new DHCP router, care must be taken to ensure the two devices don't conflict. Derek Dubout Yes, multiple DHCP servers can be both good or bad depending. As I said, I simplified a WHOLE LOT to make it somewhat understandable to those who don't know what much of this is about. And on a scale of 1 to 10 with a 10 being required to run an enterprise lan of 10,000 devices I put myself at a 4 or 5. David Ross |
