Monday, April 30, 2018

no route to host (when there is a route )

Hello,

I have encountered this issue for a while, it happens irregularly
on my systems on this lan
basically when the issue occurs
I cant route out the interface with the default route on it,
I cant ping the gateway
I cant see the arp of the gateway
but i can see the routes installed in the routing table


are there other commands I should be looking at to debug it more
Im using

ifconfig
arp
route

when i run run sh /etc/netstart em0
then normal operation returns

The only (unusual network config) im using is that im deploying
more specific static routes (than the connected route) to allow
clients on a non broadcast network to route to each other
ie if a client wants to talk to another client send packet to default gateway
(icmp redirects are off on the gateway)

the output of ping and arp when it happens are as follows
# ping 5.134.92.1
PING 5.134.92.1 (5.134.92.1): 56 data bytes
ping: sendto: No route to host
ping: wrote 5.134.92.1 64 chars, ret=-1
ping: sendto: No route to host
ping: wrote 5.134.92.1 64 chars, ret=-1
ping: sendto: No route to host
ping: wrote 5.134.92.1 64 chars, ret=-1
--- 5.134.92.1 ping statistics ---
3 packets transmitted, 0 packets received, 100.0% packet loss

#ifconfig em0
em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
lladdr 00:0d:b9:46:33:50
index 1 priority 0 llprio 3
groups: egress
media: Ethernet autoselect (100baseTX full-duplex)
status: active
inet 5.134.92.142 netmask 0xfffffc00 broadcast 5.134.95.255





below is an output of the routing table when it is not working

# route -n -T0 show
Routing tables

Internet:
Destination Gateway Flags Refs Use Mtu Prio Iface
default 5.134.92.1 UGS 2 78893 - 8 em0
224/4 127.0.0.1 URS 0 609 32768 8 lo0
5.134.92/22 5.134.92.142 UC 0 0 - 4 em0
5.134.92/23 5.134.92.1 UGS 0 80897 - 8 em0
5.134.94/23 5.134.92.1 UGS 0 396 - 8 em0
5.134.92.142 00:0d:b9:46:33:50 UHLl 0 52 - 1 em0
5.134.95.255 5.134.92.142 UHb 0 0 - 1 em0
127/8 127.0.0.1 UGRS 0 0 32768 8 lo0
127.0.0.1 127.0.0.1 UHl 1 6 32768 1 lo0
185.55.204/23 5.134.92.1 UGS 0 24 - 8 em0
185.55.206/23 5.134.92.1 UGS 0 21 - 8 em0

Internet6:
Destination Gateway
Flags Refs Use Mtu Prio Iface
::/96 ::1 UGRS
0 0 32768 8 lo0
::/104 ::1 UGRS
0 0 32768 8 lo0
::1 ::1 UHl
14 14 32768 1 lo0
::127.0.0.0/104 ::1 UGRS
0 0 32768 8 lo0
::224.0.0.0/100 ::1 UGRS
0 0 32768 8 lo0
::255.0.0.0/104 ::1 UGRS
0 0 32768 8 lo0
::ffff:0.0.0.0/96 ::1 UGRS
0 0 32768 8 lo0
2002::/24 ::1 UGRS
0 0 32768 8 lo0
2002:7f00::/24 ::1 UGRS
0 0 32768 8 lo0
2002:e000::/20 ::1 UGRS
0 0 32768 8 lo0
2002:ff00::/24 ::1 UGRS
0 0 32768 8 lo0
fe80::/10 ::1 UGRS
0 0 32768 8 lo0
fec0::/10 ::1 UGRS
0 0 32768 8 lo0
fe80::1%lo0 fe80::1%lo0 UHl
0 0 32768 1 lo0
ff01::/16 ::1 UGRS
21 21 32768 8 lo0
ff01::%lo0/32 ::1 Um
0 1 32768 4 lo0
ff02::/16 ::1 UGRS
21 21 32768 8 lo0
ff02::%lo0/32 ::1 Um
0 1 32768 4 lo0



---------------------------------------------
---------------------------------------------

below is the output of the routing table when it is working
# route -n -T0 show
Routing tables

Internet:
Destination Gateway Flags Refs Use Mtu Prio Iface
default 5.134.92.1 UGS 5 51573 - 8 em0
224/4 127.0.0.1 URS 0 1060 32768 8 lo0
5.134.92/22 5.134.92.142 UC 1 0 - 4 em0
5.134.92/23 5.134.92.1 UGS 0 116 - 8 em0
5.134.94/23 5.134.92.1 UGS 0 51 - 8 em0
5.134.92.1 de:10:0d:96:90:34 UHLc 5 180 - 4 em0
5.134.92.142 00:0d:b9:46:33:50 UHLl 0 80378 - 1 em0
5.134.95.255 5.134.92.142 UHb 0 0 - 1 em0
127/8 127.0.0.1 UGRS 0 0 32768 8 lo0
127.0.0.1 127.0.0.1 UHl 1 6 32768 1 lo0
185.55.204/23 5.134.92.1 UGS 0 12 - 8 em0
185.55.206/23 5.134.92.1 UGS 0 6 - 8 em0

Internet6:
Destination Gateway
Flags Refs Use Mtu Prio Iface
::/96 ::1 UGRS
0 0 32768 8 lo0
::/104 ::1 UGRS
0 0 32768 8 lo0
::1 ::1 UHl
14 14 32768 1 lo0
::127.0.0.0/104 ::1 UGRS
0 0 32768 8 lo0
::224.0.0.0/100 ::1 UGRS
0 0 32768 8 lo0
::255.0.0.0/104 ::1 UGRS
0 0 32768 8 lo0
::ffff:0.0.0.0/96 ::1 UGRS
0 0 32768 8 lo0
2002::/24 ::1 UGRS
0 0 32768 8 lo0
2002:7f00::/24 ::1 UGRS
0 0 32768 8 lo0
2002:e000::/20 ::1 UGRS
0 0 32768 8 lo0
2002:ff00::/24 ::1 UGRS
0 0 32768 8 lo0
fe80::/10 ::1 UGRS
0 0 32768 8 lo0
fec0::/10 ::1 UGRS
0 0 32768 8 lo0
fe80::1%lo0 fe80::1%lo0 UHl
0 0 32768 1 lo0
ff01::/16 ::1 UGRS
21 21 32768 8 lo0
ff01::%lo0/32 ::1 Um
0 1 32768 4 lo0
ff02::/16 ::1 UGRS
21 21 32768 8 lo0
ff02::%lo0/32 ::1 Um
0 1 32768 4 lo0


em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
lladdr 00:0d:b9:46:33:50
index 1 priority 0 llprio 3
groups: egress
media: Ethernet autoselect (100baseTX full-duplex)
status: active
inet 5.134.92.142 netmask 0xfffffc00 broadcast 5.134.95.255


----------------------------------------------------------------------------------
----------------------------------------------------------------------------------

No comments:

Post a Comment