Subnet Mask: 255.255.255.255

[jeddah66]

السلام عليكم ، في البيت عندي لاحظت انه المودم Linksys رابط مع المزود عن طريق ADSL وماخذ هذا قناع الشبكة


Subnet Mask: 255.255.255.255

مع اني اعرف انه مش ممكن استخدام هذا العنوان لانه خاص في عملية البث Broadcast مثل انه جهاز يبحث عن جهاز ثاني في نفس الشبكة

سؤالي هو وش الفائدة من استخدام هذا العنوان في الاعلى ؟؟؟

[one-zero]

ip= 255.255.255.255 يستخدم ل broadcast
subnetmask=255.255.255.255 او /32 تستخدم دائما مع ال loopback interface مثل اللي نعمله على الراوتر
مزيد من المعلومات هنا :

What is a /32 bit subnet mask & How can it help me?

So what is a /32 bit mask? A /32 bit mask would be 32 one's, leaving just NO zero's that could be used for host network addressing. In other words, you get just a single IP address. What use is that? Why would I want a network that has no other hosts on it and doesn't even have room for a default gateway IP address to get to other networks? Let me show you how useful this can be...

Say that we have a Cisco router. On that router we want to have a few loopback adaptors. These are virtual network adaptors that are created on the router for special purposes like representing the router as a router ID, testing, and update sources for communication. As the loopback adaptor is directly connected to the router, it doesn't need any default gateway to communicate as a PC would with the same IP address. For this reason, a loopback adaptor in a network with only a single useable IP address can still communicate because it is part of the router. Let's look at some configuration...

Say I take the IP address 1.1.1.0 and subnet it with a /30 (as we talked about above). That would give me 4 IP addresses before I subtract the network and broadcast. I could then take 3 of these IP addresses, assign them as loopback adaptors, then take the 4th IP address (the network), summarize these 3 loopback adaptors into a single IP, and advertise all 3 using a routing protocol. Here is the configuration example:

loopback 2

ip address 1.1.1.2 255.255.255.255



loopback 3

ip address 1.1.1.3 255.255.255.255



loopback 4

ip address 1.1.1.4 255.255.255.255

Router(config)# router ospf 1
Router(config-router)# area 1 range 1.1.1.0 255.255.255.252

Router(config-router)# network x.x.x.x

This would create the 3 loopback adaptors, then summarize them into a single IP address, and send them out to our other OSPF networks to allow those networks to communicate with us and for us to communicate with them.

[هندسه العاشر]

تمام اخ وبوو ولكني ارجح ان سؤال الاخ جده يعني بيه ان الاي بي اللي بتأخذه من شركه مقدمي الخدمه
وهي فكره ان يكون للانترفيس من ناحيه واحده اي بي ومن الناحيه الاخري لا يوجد وعنما يحتاج يقوم بطلب اي بي من انترفيس قريب له وليكون ايثرنيت او لوب باك
في اي حال اعتقد يوجد نبذه عن هذا الموضوع في كورس الروتينج الخاص بال CCNP