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192.168.1.37 can ping 192.168.0.22, but can't ping 192.168.0.240

subnet masks are 255.255.255.0 on all hosts in question

Switch/gateway in the middle (192.168.1.253) can ping both of these addresses, and it also contains a correct ARP entry for 192.168.0.240

When I run tracert on 192.168.1.37, pointing to 192.168.0.22 I get a tracert response:

1 1 ms <1 ms <1 ms 192.168.1.253

2 <1ms <1 ms <1 ms 192.168.0.22

But there is no tracert response when I point it to 192.168.0.240. When I check the wireshark trace for ICMP responses - there are none! Looks like the gateway is not responding to ICMP packet sent to that remote address at all.

What else can I check? Any ideas?

UPDATE: Both 192.168.0.22 and 192.168.0.240 have the same default gateway defined. I can ping 192.168.1.37 from 192.168.0.22 but not from 192.168.0.240

UPDATE 2: When I change IP address on the 'difficult' host from 192.168.0.240 to 192.168.0.34 everything works well! When I change it back to .240 it stops responding to pings from the other subnet. What is causing it? We are running a bit short on IP addresses, so it would be good to know why .240 doesn't work.

  • Check that the 240 host has the correct default gateway. – Ron Trunk Aug 27 '17 at 11:22
  • Yes, it does. Thank you for the comment - will add it to the answer – Tony Sepia Aug 27 '17 at 11:23
  • Can you ping the other way? Does the host have a firewall ? – Ron Trunk Aug 27 '17 at 11:23
  • added updates to the question! – Tony Sepia Aug 27 '17 at 11:40
  • (ICMP) Filtering on the gateway router or switch? – Zac67 Aug 27 '17 at 12:24
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We have cleared ARP table on both hosts and the switch. That has somehow resolved the problem, despite the fact that we have previously manually checked that the ARP table on the switch contains a correct entry:

show ip arp | grep 0.240

  • You should accept your answer so that the question doesn't keep popping up forever, looking for an answer. – Ron Maupin Sep 26 '17 at 17:11

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