In this tutorial, we will discuss the different reasons that cause the destination host unreachable in the Cisco packet tracer
Many times we encountered with destination host unreachable error when creating network topologies in packet tracer.
This error can also occur in case of hardware failures or faults however that is not so common.
As packet tracer is a simulation so we cannot have hardware failures in it so most of the time, this error is observed in packet tracer due to the following reasons.
Download
Reason 1
Pinging IP address that does not exist on the network
Many times while testing our network, we mistype the commands and IP addresses so In case if we have mistyped the IP address that does not exist in our network will cause the Destination host unreachable error.
Fix – Make sure you have typed the destination IP correctly while pinging.
Reason 2
The router does not have an entry in the routing table
If the destination IP is on the other network then the router should have the information about that network in its routing table otherwise it will cause the destination host unreachable because even though the host exists but our device does not know how to reach the host.
If we will ping the Fast Ethernet 0/0 interface of router 4 from PC0 then we will get the unreachable error.
Download this Lab and try pinging the router 4 interface.
Fix – fix the issue by enabling routing dynamically or manually. Once router 3 will have information about the 192.168.3.0 network then router 3 will send the ping response.
Reason 3
Access list blocking the traffic
If traffic from any host is blocked by the access list then a destination host unreachable error will be received.
In the below example, traffic from host PC0 is blocked from reaching network 192.168.3.0 so the router is dropping the traffic received from this host, and ping packets are not able to reach the host PC1.
Download the lab and test the ping command and you will be able to see the packets blocked by the access list.
Fix – To fix the issue, either disable the access list or allow the traffic from PC0 on network 192.168.3.0
If we do not want to allow all traffic then only ICMP traffic can be blocked on the network. An extended access list can be used to block only ICMP traffic and allow the rest of the traffic from the host.
I tried to build a simple network in Packet Tracer and I get “Destination host unreachable” when I try pinging a PC from another network.
Pinging PCs from the same network works.
When I use tracert to a PC from another network it stops at the current network default gateway.
My guess it’s that it has something to do with the connections between the two routers, but I have no idea what exactly.
I would be really grateful if someone could help me solve this problem. Thank you in advance.
Here is the image of the network.
Router 0 configuration :
ROOM1#show running-config
Building configuration...
Current configuration : 799 bytes
!
version 15.1
no service timestamps log datetime msec
no service timestamps debug datetime msec
no service password-encryption
!
hostname ROOM1
!
!
!
!
!
!
!
!
ip cef
no ipv6 cef
!
!
!
!
license udi pid CISCO1941/K9 sn FTX1524U1YC-
!
!
!
!
!
!
!
!
!
!
!
spanning-tree mode pvst
!
!
!
!
!
!
interface GigabitEthernet0/0
ip address 192.168.0.1 255.255.255.240
duplex auto
speed auto
!
interface GigabitEthernet0/1
no ip address
duplex auto
speed auto
shutdown
!
interface Serial0/0/0
ip address 192.168.0.253 255.255.255.252
tx-ring-limit 10000
clock rate 128000
!
interface Serial0/0/1
no ip address
clock rate 2000000
shutdown
!
interface Vlan1
no ip address
shutdown
!
ip classless
!
ip flow-export version 9
!
!
!
!
!
!
!
!
line con 0
!
line aux 0
!
line vty 0 4
login
!
!
!
end
Router 1 configuration :
ROOM2#show running-config
Building configuration...
Current configuration : 781 bytes
!
version 15.1
no service timestamps log datetime msec
no service timestamps debug datetime msec
no service password-encryption
!
hostname ROOM2
!
!
!
!
!
!
!
!
ip cef
no ipv6 cef
!
!
!
!
license udi pid CISCO1941/K9 sn FTX152462Z7-
!
!
!
!
!
!
!
!
!
!
!
spanning-tree mode pvst
!
!
!
!
!
!
interface GigabitEthernet0/0
ip address 192.168.0.17 255.255.255.240
duplex auto
speed auto
!
interface GigabitEthernet0/1
no ip address
duplex auto
speed auto
shutdown
!
interface Serial0/0/0
ip address 192.168.0.254 255.255.255.252
tx-ring-limit 10000
!
interface Serial0/0/1
no ip address
clock rate 2000000
shutdown
!
interface Vlan1
no ip address
shutdown
!
ip classless
!
ip flow-export version 9
!
!
!
!
!
!
!
!
line con 0
!
line aux 0
!
line vty 0 4
login
!
!
!
end
asked Dec 11, 2020 at 14:46
EuLaur DEuLaur D
31 gold badge1 silver badge3 bronze badges
7
You can’t ping because neither router knows how to get to the opposite network.
You need to either:
- Configure static routes on the routers. Router 0 needs to know how to get to 192.168.0.16/28. For example,
ip route 192.168.0.16 255.255.255.240 192.169.0.254
Similarly, you need a static route on router1 for 192.168.0.0/28
OR
- Configure a routing protocol on both routers so they can exchange routing information. You can use OSPF or EIGRP. You can also use RIP, but most consider it an obsolete protocol.
answered Dec 11, 2020 at 15:14
Ron TrunkRon Trunk
65.9k5 gold badges62 silver badges125 bronze badges
5
Сообщение от natashaa
Мы прописали маршрут по умолчанию
да
Сообщение от natashaa
А почему тогда для R0 не надо было его прописывать?
а он там уже прописан был
================================================== ======
natashaa, я тебя в заблуждение ввел…….извиняюсь, в голове много всего другого, не вспомнил вчерашнее задание.
Сообщение от natashaa
Мы прописали маршрут по умолчанию?
нет
мы прописали маршрут до конкретной сети 192.168.15.0
а вот на R0 был прописан маршрут по умолчанию
в принципе, по твоей схеме, если вместо маршрута
Код
ip route 192.168.15.0 255.255.255.248 209.16.52.1
ты пропишешь маршрут по умолчанию
Код
ip route 0.0.0.0 0.0.0.0 209.16.52.1
ничего не изменится, у тебя всего два роутера и 3 подсети
Pfrozen
Знаток
(479),
закрыт
2 года назад
Задание с командой ip route. Вроде все правильно ввёл а он это: destination host unreachable. Ping я понимаю идёт, но чего то не хватает?
Spoilerok
Высший разум
(274387)
2 года назад
У вас gateway неправильно задан.
PfrozenЗнаток (479)
2 года назад
Так и не понял (
Spoilerok
Высший разум
(274387)
Pfrozen, что бы это работало, надо что бы у роутеров были интерфейсы с ip адресами из одной сети. У вас же все адреса не пересекаются.
PfrozenЗнаток (479)
2 года назад
Хм. Я делаю по заданию. И типа эти настройки не будут работать?
Spoilerok
Высший разум
(274387)
Pfrozen, 192.168.3.1 и 3.2 в одном диапазоне. Значит на первом gateway будет 192.168.3.2 а на втором 3.1
PfrozenЗнаток (479)
2 года назад
ещё хуже
Spoilerok
Высший разум
(274387)
Pfrozen, у вас эти интерфейсы соединены на схеме?
Here we are going to see ping responses network unreachable,request timed out,success with a simple topology by adding static route on each router step by step.
Step 1:Create a topology like this
Step 2:Routers only knows directly connected network,there is no static route added.Now, ping default gate way 10.0.0.1 from Host 10.0.0.10. we will get reply from 10.0.0.1.Because router knows 10.0.0.0 network.
ping 10.0.0.1
PC>ping 10.0.0.1
Pinging 10.0.0.1 with 32 bytes of data:
Reply from 10.0.0.1: bytes=32 time=157ms TTL=255
Reply from 10.0.0.1: bytes=32 time=16ms TTL=255
Reply from 10.0.0.1: bytes=32 time=29ms TTL=255
Reply from 10.0.0.1: bytes=32 time=31ms TTL=255
Ping statistics for 10.0.0.1:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 16ms, Maximum = 157ms, Average = 58ms
Step 3:Now ping host 40.0.0.10,we will get
PC>ping 40.0.0.10
Pinging 40.0.0.10 with 32 bytes of data:
Reply from 10.0.0.1: Destination host unreachable.
Reply from 10.0.0.1: Destination host unreachable.
Reply from 10.0.0.1: Destination host unreachable.
Reply from 10.0.0.1: Destination host unreachable.
Ping statistics for 40.0.0.10:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
Because Router R1 doesn’t know about the network 40.0.0.0.So we will get reply from 10.0.0.1 destination host unreachable.Check rouing table of R1 by giving command
R1#show ip route
Codes: C – connected, S – static, I – IGRP, R – RIP, M – mobile, B – BGP
D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP
i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area
* – candidate default, U – per-user static route, o – ODR
P – periodic downloaded static route
Gateway of last resort is not set
C 10.0.0.0/8 is directly connected, FastEthernet0/0
C 20.0.0.0/8 is directly connected, Serial2/0
Step 4:Add static route to Router R1 for the network 40.0.0.0
R1(config)#ip route 40.0.0.0 255.0.0.0 20.0.0.2
Now,Packets that came to Router R1 for the network 40.0.0.0 will be forwarded to 20.0.0.2
Check Routing table of R1 by giving command,
R1#show ip route
Codes: C – connected, S – static, I – IGRP, R – RIP, M – mobile, B – BGP
D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP
i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area
* – candidate default, U – per-user static route, o – ODR
P – periodic downloaded static route
Gateway of last resort is not set
C 10.0.0.0/8 is directly connected, FastEthernet0/0
C 20.0.0.0/8 is directly connected, Serial2/0
S 40.0.0.0/8 [1/0] via 20.0.0.2
Step 5:Now ping ip address 20.0.0.1,that is connected to Router R1 by giving command
PC>ping 20.0.0.1
Pinging 20.0.0.1 with 32 bytes of data:
Reply from 20.0.0.1: bytes=32 time=31ms TTL=255
Reply from 20.0.0.1: bytes=32 time=16ms TTL=255
Reply from 20.0.0.1: bytes=32 time=32ms TTL=255
Reply from 20.0.0.1: bytes=32 time=31ms TTL=255
Ping statistics for 20.0.0.1:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 16ms, Maximum = 32ms, Average = 27ms
We get reply from 20.0.0.1 because router R1 knows directly connected network.
Step 6:Now ping ip address 20.0.0.2
PC>ping 20.0.0.2
Pinging 20.0.0.2 with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Ping statistics for 20.0.0.2:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
Router R2 doesn’t know about the network 10.0.0.0.So we can’t get reply from R2.Now add static route to router R2 for network 10.0.0.0 .Check routing table of R2
R2#show ip route
Codes: C – connected, S – static, I – IGRP, R – RIP, M – mobile, B – BGP
D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP
i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area
* – candidate default, U – per-user static route, o – ODR
P – periodic downloaded static route
Gateway of last resort is not set
C 20.0.0.0/8 is directly connected, Serial2/0
C 30.0.0.0/8 is directly connected, Serial3/
Step 7:Add Static route to network 10.0.0.0 in R2
R2(config)#ip route 10.0.0.0 255.0.0.0 20.0.0.1
R2#show ip route
Codes: C – connected, S – static, I – IGRP, R – RIP, M – mobile, B – BGP
D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP
i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area
* – candidate default, U – per-user static route, o – ODR
P – periodic downloaded static route
Gateway of last resort is not set
S 10.0.0.0/8 [1/0] via 20.0.0.1
C 20.0.0.0/8 is directly connected, Serial2/0
C 30.0.0.0/8 is directly connected, Serial3/0
Step 8:Now ,ping 20.0.0.2 we get
PC>ping 20.0.0.2
Pinging 20.0.0.2 with 32 bytes of data:
Reply from 20.0.0.2: bytes=32 time=63ms TTL=254
Reply from 20.0.0.2: bytes=32 time=62ms TTL=254
Reply from 20.0.0.2: bytes=32 time=62ms TTL=254
Reply from 20.0.0.2: bytes=32 time=62ms TTL=254
Ping statistics for 20.0.0.2:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 62ms, Maximum = 63ms, Average = 62ms
After that, ping 40.0.0.10
PC>ping 40.0.0.10
Pinging 40.0.0.10 with 32 bytes of data:
Reply from 20.0.0.2: Destination host unreachable.
Reply from 20.0.0.2: Destination host unreachable.
Reply from 20.0.0.2: Destination host unreachable.
Reply from 20.0.0.2: Destination host unreachable.
Ping statistics for 40.0.0.10:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
Step 9:We get reply from 20.0.0.2 as Destination host unreachable.So ,we have to add 40.0.0.0 network to R2
R2(config)#ip route 40.0.0.0 255.0.0.0 30.0.0.2
R2#show ip route
Codes: C – connected, S – static, I – IGRP, R – RIP, M – mobile, B – BGP
D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP
i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area
* – candidate default, U – per-user static route, o – ODR
P – periodic downloaded static route
Gateway of last resort is not set
S 10.0.0.0/8 [1/0] via 20.0.0.1
C 20.0.0.0/8 is directly connected, Serial2/0
C 30.0.0.0/8 is directly connected, Serial3/0
S 40.0.0.0/8 [1/0] via 30.0.0.2
Step 10: Ping 30.0.0.1 and see what we get,
PC>ping 30.0.0.1
Pinging 30.0.0.1 with 32 bytes of data:
Reply from 10.0.0.1: Destination host unreachable.
Reply from 10.0.0.1: Destination host unreachable.
Reply from 10.0.0.1: Destination host unreachable.
Reply from 10.0.0.1: Destination host unreachable.
Ping statistics for 30.0.0.1:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
Step 11: Add static route to Router R1 for the network 30.0.0.0
R1(config)#ip route 30.0.0.0 255.0.0.0 20.0.0.2
Check Routing table of Router R1,
R1#show ip route
Codes: C – connected, S – static, I – IGRP, R – RIP, M – mobile, B – BGP
D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP
i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area
* – candidate default, U – per-user static route, o – ODR
P – periodic downloaded static route
Gateway of last resort is not set
C 10.0.0.0/8 is directly connected, FastEthernet0/0
C 20.0.0.0/8 is directly connected, Serial2/0
S 30.0.0.0/8 [1/0] via 20.0.0.2
S 40.0.0.0/8 [1/0] via 20.0.0.2
Now , ping 30.0.0.1,
PC>ping 30.0.0.1
Pinging 30.0.0.1 with 32 bytes of data:
Reply from 30.0.0.1: bytes=32 time=63ms TTL=254
Reply from 30.0.0.1: bytes=32 time=62ms TTL=254
Reply from 30.0.0.1: bytes=32 time=62ms TTL=254
Reply from 30.0.0.1: bytes=32 time=63ms TTL=254
Ping statistics for 30.0.0.1:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 62ms, Maximum = 63ms, Average = 62ms
Step 12: Ping 30.0.0.2 and see what we will get,
PC>ping 30.0.0.2
Pinging 30.0.0.2 with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Ping statistics for 30.0.0.2:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
Router R3 doesn’t know about the network 10.0.0.0.
Step 13:Add network 10.0.0.0 &20.0.0.0 by using static route command.
R3(config)#ip route 10.0.0.0 255.0.0.0 30.0.0.1
R3(config)#ip route 20.0.0.0 255.0.0.0 30.0.0.1
R3#show ip route
Codes: C – connected, S – static, I – IGRP, R – RIP, M – mobile, B – BGP
D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP
i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area
* – candidate default, U – per-user static route, o – ODR
P – periodic downloaded static route
Gateway of last resort is not set
S 10.0.0.0/8 [1/0] via 30.0.0.1
S 10.0.0.0/8 [1/0] via 30.0.0.1
C 30.0.0.0/8 is directly connected, Serial3/0
C 40.0.0.0/8 is directly connected, FastEthernet0/0
Now ,ping 40.0.0.10
PC>ping 40.0.0.10
Pinging 40.0.0.10 with 32 bytes of data:
Reply from 40.0.0.10: bytes=32 time=125ms TTL=125
Reply from 40.0.0.10: bytes=32 time=110ms TTL=125
Reply from 40.0.0.10: bytes=32 time=110ms TTL=125
Reply from 40.0.0.10: bytes=32 time=125ms TTL=125
Ping statistics for 40.0.0.10:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 110ms, Maximum = 125ms, Average = 117ms
Finally we get reply from 40.0.0.10 .
Step 14: Now go host 40.0.0.10 and ping host 10.0.0.10 and check whether we can ping or not..
PC>ping 10.0.0.10
Pinging 10.0.0.10 with 32 bytes of data:
Reply from 10.0.0.10: bytes=32 time=109ms TTL=125
Reply from 10.0.0.10: bytes=32 time=125ms TTL=125
Reply from 10.0.0.10: bytes=32 time=125ms TTL=125
Reply from 10.0.0.10: bytes=32 time=125ms TTL=125
Ping statistics for 10.0.0.10:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 109ms, Maximum = 125ms, Average = 121ms
Three types of reply we got
Reply
Destination host unreachable
Request timed out
In Router,
For,Reply- !!!!!
Destination host unreachable- UUUUU
Request timed out- …….
