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I've been working with the ip 192.168.7.0 / 27 with jump 32, when I wanted to put 96 it no longer works for me and it says that the mask is an error.

192.168.7.96 255.255.255.224

MESSAGE FROM CISCO: BAD MAS / 27 TO 192.168.7.96

eh venido trabando con las ip 192.168.7.0 /27 con salto 32 , cuando eh querido poner la 96 ya no me funciona y dice que la mascara es un error.

192.168.7.96 255.255.255.224

MENSAJE DE CISCO : BAD MAS /27 TO 192.168.7.96

Ron Trunk
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Francine Guerrero
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  • Does this answer your question? [How do you calculate the prefix, network, subnet, and host numbers?](https://networkengineering.stackexchange.com/questions/7106/how-do-you-calculate-the-prefix-network-subnet-and-host-numbers) – Jesse P. Sep 14 '21 at 00:57
  • Did any answer help you? if so, you should accept the answer so that the question does not keep popping up forever, looking for an answer. Alternatively, you could post and accept your own answer. – Ron Maupin Dec 23 '21 at 21:35

3 Answers3

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I assume you tried to configure an interface with IP 192.168.7.96/27.

This cannot be done, since 192.168.7.96 is the network address of the network 192.168.7.96/27. Network and broadcast addresses cannot be assigned to an interface.

You can use 192.168.7.97/27, which is the first available IP of this network.

JFL
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  • Supongo que intentó configurar una interfaz con IP 192.168.7.96/27. Esto no se puede hacer, ya que 192.168.7.96 es la dirección de red de la red 192.168.7.96/27. Las direcciones de red y de difusión no se pueden asignar a una interfaz. Puede utilizar 192.168.7.97/27, que es la primera IP disponible de esta red. – Ron Trunk Sep 13 '21 at 19:23
  • CONFUGURI UN ROUTER CON 192.168.7.0 , LA SIGUIENTE CON 192.168.7.32 , DESPUES 192.168.7.64 , PORQUE NO PODRIA FUNCIONAR CON 192.168.7.96 , SI CON LAS OTRAS IP SI LAS PUDE HACER ?? – Francine Guerrero Sep 13 '21 at 19:48
  • Por favor, edite su pregunta para incluir la configuración completa del rutador. Edit your question to include the full router configuration – Ron Trunk Sep 13 '21 at 19:56
  • And I thought this was an English site... Aber wer weiß das so genau?... – Zac67 Sep 13 '21 at 20:07
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    CAPS IS OFFENSIVE....I AM OFFENDED – manish ma Sep 13 '21 at 20:13
  • pude configurar perfectamente con 192.168.7.32 , después con 192.168.7.64 , la siguiente debería ser 192.168.7.96 y me dice que las mascara 255.255.255.224 no es compatible – Francine Guerrero Sep 13 '21 at 20:37
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    @FrancineGuerrero if you actually managed to set 192.168.7.32/27 or 192.168.7.64/27 on a router interface, then this is a bug of the product you are using (is it in packet tracer?). – JFL Sep 14 '21 at 06:54
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You cannot use any IPv4 address that has all host-part bits set to zero. That is the network address or subnet address that cannot be used as host address by convention. Nearly all devices reject such a configuration.

255.255.255.224 or /27 uses the first three octets and the first three bits of the last octet - 27 bits in total - for the network address, and the remaining five bits for the host part. Accordingly, the last octets 0, 32, 64, 96, 128, ... (multiples of 25) cannot be used for addressing a host in a /27 subnet.

A host part with all ones cannot be used either, as that address is the subnet's directed broadcast address (for /27 that's the last octet with 31, 63, 95, 127, ...).

PS: As @JörgWMittag has correctly pointed out, the special /31 peer-to-peer subnet from RFC 3021 does allow using 0 and 1 in the host bit, but it's the only exception to the rule.

Zac67
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    "You cannot use any IPv4 address that has all host-part bits set to zero" – RFC 3021 slightly muddies the water here, though. – Jörg W Mittag Sep 16 '21 at 19:53
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En 3 routerenter image description heres pude configurar perfectamente con 192.168.7.32 , después con 192.168.7.64 , la siguiente debería ser 192.168.7.96 y me dice que las mascara 255.255.255.224 no es compatible

Francine Guerrero
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    @Peregrino69 No. You can’t force users to speak in any particular language. If they don’t speak English, they’d be forced to use a translation service, which is just as easy for you to use to translate their native language into yours. – Jesse P. Sep 13 '21 at 22:18
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    @JesseP. Ah, my apology to the OP (& community of course). That seems to have changed in the past couple of years I've been out of the game. I do remember seen it expressed exactly like that before, several times. Not on which site, tho. Thanks for letting me know. Rebuttal removed, remembering :-) – Peregrino69 Sep 13 '21 at 22:46
  • @Peregrino69 No worries. – Jesse P. Sep 13 '21 at 22:46