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Member

Registered: 2007-02-27

Posts: 174

arp weirdness, can't ping from lan to lan

Hi,

I'm confounded by a problem I've been having lately.  I have two machines, A and B connected wirelessly to a Linksys WRT54GL router.

They have static IPs.

A is a server, B is a laptop.

When I run

arp -an

on B, I see:

# arp -an
? (machine.A.ip) at <incomplete> on wlan0
? (router.ip) at machine:A:mac:address [ether] on wlan0

The flaky thing about this is that about half the time I can ping from B to A.  The rest of the time I get destination host unreachable.  Any ideas?  It's driving me nuts.

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revellion

Member

From: Sweden

Registered: 2007-04-10

Posts: 54

Re: arp weirdness, can't ping from lan to lan

The server is connected by wireless using a dongle or is it on wired on the linksys?

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Member

Registered: 2007-02-27

Posts: 174

Re: arp weirdness, can't ping from lan to lan

Wireless.

I'm thinking the problem is related to ufw.  Do you know if there are any special rules required to make hosts accessible to one another on a LAN?

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Strike0

Member

From: Germany

Registered: 2011-09-05

Posts: 1,429

Re: arp weirdness, can't ping from lan to lan

I'm thinking the problem is related to ufw.  Do you know if there are any special rules required to make hosts accessible to one another on a LAN?

No special rules are necessary for ping/echo reply in the ufw default modes, no. Whether you mean that with "accessible" I am not sure. Have a look here.

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Member

Registered: 2007-02-27

Posts: 174

Re: arp weirdness, can't ping from lan to lan

I'm fairly certain that I have solved this.  The server machine, the one whose arp entry was incomplete in A's table, is connected to the LAN by a wireless card.  I had to add this line to my netcfg settings for the server:

ROUTES=('ip of LAN router')

Now I can manually delete the server's arp entry from the laptop's table, ping the server from the laptop, and the arp request is no longer listed as incomplete.  Hooray!

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