He,He, As an @Home guy, let me tell you something

hillman(山大王)

本文发表在 rolia.net 枫下论坛Most @Home subscribers use 1 v 1 DHCP that means you will get the same ip every time.

The progress is like following:
1. When your Cable modem turned on, it will send DHCPDISC to Cable Router in our Regional Center. Normaly it is a Cisco, some are Motorola or 3COM. The cable router check its "IP-HELPER" then send your broadcast to DHCP Server.

2. DHCP servers are normaly SUN E4500 Clusters, it uses Cisco AIC DHCP software or JOIN DHCP software. We are now slowly immigrating from Cisco AIC to JOIN because CISCO one are unneccessarily complicate. When DHCP receive your DHCPDESC, it will send back a DHCPOFFER which contains the available servers info.

3. Your Cable Modem then send back a DHCPREQ, the Server use your
Cable modem's MAC address to contact its database using LDAP.
When it found the ip according to your MAC, then will give back a DHCPACK.

4. Your Cable modem got the ip and finished its init. It's turn for your Computer.
Your login program send out your Customer ID (CPE_ID) through the Cable modem.
DHCP server use your CustomerID to query the database to find out
your ip then same way give back a DHCPACK, telling you the DNS server address and Your Gateway address.
Now you can surf.

So.
In most cases, you can set your ip as a static one. Remember to setup
correct DNS address and Gateway address.
Some of Rogers' Head End use Dynamic one ( very few), they will give a new CPE Ip address from its ip pool every time.
You will cause conflict if they made changes to the ip block planning.
We always block you if that happens. :)

After all, it is safe to set your ip to a static one.更多精彩文章及讨论，请光临枫下论坛 rolia.net

(#122972@0)
Last Updated: 2001-7-7
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3 MTHS -slimpiggy(Aiya Kar-Ching); 2001-7-6 (#122256@0)

我刚装了1个月不到，变过一次 -yellow(yellow); 2001-7-6 (#122339@0)

7个月了，没变过 -000(老九); 2001-7-6 (#122345@0)

注：我用的是DHCP, 一开始我也问过这个问题，他们说他们不保证不变，但一般还是不变的 -000(老九); 2001-7-6 (#122355@0)

DHCP server在你注册时分配的IP,有一定的有效期,就是说,如果在expire date之前你登陆了,IP地址就会跟原来一样,也就是说,如果你的未登陆时间超过有效期,再次登陆时以前的IP就有可能变了 -shou(小受); 2001-7-6 (#122371@0)

关键是看你用固定IP还是DHCP了，这个是由@HOME决定的 -flipflop(翻云覆雨); 2001-7-6 (#122347@0)

是Dynamic or fix,你自己也可以决定的,方法如下: 1, 动态IP,很简单,设置DHCP分配IP Address; 2,静态IP Address, 将你第一次登陆时被分配的IP Address记录下来,以及其他的servers,然后手工设置你的Network,搞定 -shou(小受); 2001-7-6 (#122372@0)

high hand, 佩服佩服 -000(老九); 2001-7-6 (#122378@0)
第二个方法根本不可靠。如果人家强制你DHCP，而你非要占用原来的IP，会和别人冲突的，但我相信rogers应该会避免这种无政府主义的出现，所以结论是，私自设立的静态IP很可能无效。 -guest:; 2001-7-6 (#122399@0)

这种方法理论上不对，用在其他地方也不可靠，但用在rogers上是可行的，因为据我观察，即使关上几天不用，重新上网以后的IP还是原来的 -000(老九); 2001-7-6 (#122411@0)

问这个问题的目地当然是想看看用DHCP动态分配时，ROGERS有多大可能得到同样的IP。静态设定当然啦，但人家是要求你别这样做，我想如果这样做，查出后ROGERS有权力告你。 -whitetiger(whitetiger); 2001-7-6 (#122618@0)

Although Rogers is using DHCP, the IP address you get is relatively static... -dennis2(Dennis); 2001-7-6 {650} (#122645@0)
As far as I know, rogers is using host name as DHCP client identifier. So on their end, they just bundle IP with hostname. If they want to change, they just change the IP bundled with that hostname. This way, they have control over IP assigning.

Cable connection can be always online so unlike dialup (which a lot more users share a relatively small pool of IP) it makes very little sense for Rogers to change IP often. The exception would be if someone abuses the service, say running a warez or porn site that generate a lot of traffic, then they might change IP for that user. (Well at least that's the case of the former owner of my last IP.)

Yeah, I was waken up at 8:00am one Saturday morning telling me that I was using other people's IP... -dennis2(Dennis); 2001-7-6 {554} (#122420@0)
because I set it to use static IP and thought it would never change.

The worst thing was that the former owner of my new IP used to run a pretty busy web site, so I got a lot of hits from all over the world (esp. from search engine).

Anyway, I got another IP now after switching to Shaw. So I got my IP changed twice.

Just FYI, if you are going to put your machine directly on the Internet, be sure to update it to the lastest patch. I heard that a stock installation of Redhat got hacked after only one or two weeks of exposure on the Internet.
如果你很长时间不用,设置的静态IP当然会跟别人冲突. 如果你很久都不用它,要静态的做什么用? -shou(小受); 2001-7-6 (#122498@0)

建议如果没得到@HOME许可的花不要随便设置静态IP，因为你从DHCP获得的地址是DHCP Server从IP Spool里分配的，和静态IP的网段不同，意味着可能会在IP Lease期限到期后被重新分配出去。如果和别人的IP冲突了而对方complain的话，可能会有麻烦。 -flipflop(翻云覆雨); 2001-7-6 (#122465@0)

要用固定IP,又不跟人冲突,建议就是:别关机,准确的说,是, 别断开与网络的连接,即使你很久不用,也不断开 -shou(小受); 2001-7-6 (#122503@0)

It will not work. When lease expires, you will have to renew the IP. They can just give you an NACK and give you a new one. It doesn't matter whether your machine is always up or not. -dennis2(Dennis); 2001-7-6 (#122514@0)

看来你算是明白人。呵呵，shou不是做网管的或安全分析的吧？ -guest:; 2001-7-6 (#122579@0)
Yes! -whitetiger(whitetiger); 2001-7-6 (#122623@0)
我使用的过程中IP除了搬家外没有改变过。可能在于对lease期限的理解跟我不一样，我认为是从最后一次断开网络连接到下一次注册之间的时间间隔，而不是两次登陆时间的间隔。如果照你的说法，一直使用该IP时也可能发生IP突然被修改的情况，这样的结论我觉得是不成立的。 -shou(小受); 2001-7-6 {34} (#122848@0)
我不是网管，以前只是写过网管程序。

计费程序？呵呵 -guest:; 2001-7-6 (#122859@0)

SNMP based NM system -shou(小受); 2001-7-6 (#122866@0)

具体说，就是在你一直用同一个IP时（指正在进行网络访问），会发现自己的IP变了?只要你IP分配时间超过lease期限,不管是否你一直持续使用该IP,期间没有任何重启，网络连接断开等情况发生？举个例子： -shou(小受); 2001-7-6 {108} (#122864@0)
期限是2周，那如果我持续不断上网2周，当然这个是假设，会在最后一天发现IP在我正在上网使用时突然变成了另外一个？

建议你先看看书，有一些基本的DHCP协议中的定义概念，看过就知道了，不难。 -guest:; 2001-7-6 (#122869@0)

恩，2年前看过，的确记不清了，谁有书的能否借来看看？如果我说错了，请指正，大家需要的是正确信息，不是废话 -shou(小受); 2001-7-6 (#122873@0)
hmm,老兄能不能堂堂正正做人，光明正大说话？免得以后想请教问题不知道找谁，谢了 -shou(小受); 2001-7-6 (#122886@0)

你忒敏感，我现在怎么就偷偷摸摸了？既然rolia赋予guest同样的权利，我和你无非象加拿大PR和citizen的关系，我不比你低一等吧？我不见得不光明正大吧？呵呵，我们还是讨论技术好了:) -guest:; 2001-7-6 (#122889@0)

恩，说得有理，可是做的却是另外一套。你继续说，我睡觉去了 -shou(小受); 2001-7-7 (#122955@0)
联想比较丰富的应该不是我吧，没说你低人一等，而是我对这样的行为比较看不起，呵呵。惹不起，躲行不行？ -shou(小受); 2001-7-7 (#122959@0)

看来你还不是很明白@home的做法。事实上@home的用户在申请时都会分配一个主机名和固定的IP，两年前他们就是这样“一丝不苟”的工作。只不过后来他们发现这样的工作量太大，就不去再管你用不用他给的IP。（工作人员亲口说的）。 -heian(黑暗天使); 2001-7-7 {82} (#122984@0)
到现在我都很怀念以前给我的那个IP，太好记了。不过因为搬过家，只有忍痛重新找了个：（

你说的是给分配了固定IP的情况，但是有不少用户是没有被分配固定IP的。 -flipflop(翻云覆雨); 2001-7-9 (#124688@0)

do you want to setup Cisco Lab? -songl(风); 2001-7-6 (#122855@0)

Tooo expensive. -whitetiger(whitetiger); 2001-7-6 (#122895@0)

是啊，cisco在建威大厦的lab据说是500万美元的，也还不是顶级的，我当初好想在里面混个ccie出来啊。 -guest:; 2001-7-7 (#122915@0)
since each of us here would have some Cisco or network equipment, like router, switch, modem, etc. why don't we connect them together? -songl(风); 2001-7-7 (#122932@0)

other issue on Rogers cable: I running Netscape on unix via Rogers cable. sth seems strange, probably in Rogers servers for connecting and IP assigning. Anyone else encounter such problem? -guest:guest; 2001-7-6 (#122871@0)

He,He, As an @Home guy, let me tell you something -hillman(山大王); 2001-7-7 {1648} (#122972@0)

小受说的是事实。如果始终使你的IP alive，那么就不会改变。所以我使用ROUTER，它可以Keep IP alive。GUEST说的也对，如果DHCP已经将你的IP分配给别人，那么如果强制使用这个IP，将不能访问网络。所以说使用固定IP的前提是KEEP IP ALIVE，这样@home就不会回收。 -heian(黑暗天使); 2001-7-7 {123} (#122974@0)

我的IP已经用了快一年了。@HOME的DHCP有效期一般是一周，由于ROUTER不关，所以一直保持着。这是实际发生的，我没有胡编，欢迎讨论。

You are right. In most cases, the lease is 7 days. Even for the Dynamic DHCP, if you are using the ip, you will get lease extended ( or renewed) using the same ip. -hillman(山大王); 2001-7-7 (#122985@0)
Maybe, if the router always send alive packet out, then the DHCP will not recycle this IP.But normally the pc will not send the keeping alive packets. -whitetiger(whitetiger); 2001-7-8 (#124576@0)

我用IPCONFIG在NT下运行,看不见结果? HOW CAN I DO? -farmer(农夫); 2001-7-9 (#125031@0)

ipconfig /all -whitetiger(whitetiger); 2001-7-9 (#125052@0)

doesn't work. same as before -farmer(农夫); 2001-7-9 (#125055@0)
It works under "Command Prompt" not under "RUN" from "START" -farmer(农夫); 2001-7-10 (#127097@0)
winipcfg(winNT), whitetiger win cisco.能象你就好了。 -flyeve2(keeving); 2001-7-13 (#131354@0)

@Montreal

He,He, As an @Home guy, let me tell you something

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