AIX

Hi All,
I'm testing ping command on two servers.
[say A-->B and C--->D]
A,B,C,D are servers

From A-->B:
ping -c 3 -p ff -s30720 <B IP-Addres>
This works fine.

From C-->D:
ping -c 3 -p ff -s30720 <D IP-Addres>
This is NOT working and 100% packe loss
But if I use 8700 instead of 30720 for packet size '-s', then it works.

Now, Kindly let me know which variable is restricting this packet size '-s' and how to increase it in AIX server??

Thanks in Advance.

How do you know it is not a network restriction instead of an AIX setting?

What does the ethernet adapter and interface attribute settings on all four systems show?

It looks to be a packet size issue so check on each adapter and interface on each system:
lsattr -El enx
lsattr -El entx
Where enx/entx it the adapter/interface, like en0, en1, en2 or ent0, ent1, ent2, Etc.

Look at the mtu packet size, jumbo frames, large send, Etc.

HTH

Do the packets traverse the same physical network ? Perhaps the second one has a router on the network that is throwing away the large icmps?

No in different physical network:

A & B in different segment

say for ex

A--> 10.172.10.X ; B--> 10.172.30.X

But C & D are in same segment:

C--> 10.173.10.X; D--> 10.173.10.X

Sounds like a network problem then.
The busintr shouldn't make any difference.
I would suspect the problem network is not enabled for large send.

Might be worth using "traceroute" to get a list of routers between the two destinations and then trying the ping of the large packet. TBH, from the articles Ive read it seems that the large ICMP packets (over 1492) are handled in vastly different ways by differing network equipment, so I wouldnt expect consistancy.