My Win95 pc's can't ping my 772 router, but my NT server can?

[KFCColonel]

I have 9 pc's (all Win 95) connected to a hub. Connected to the same hub is a NT Server (BDC). Connected to the hub is a Cisco 772m Router with an ISDN line going back to the home office network.

The NT server authenticates the 9 pc's just fine and the NT server can ping the 772 router and connect back to the home office network, but the 9 win 95 pc's can't ping the router and can't get back to the home office network.

The 9 pc's have only TCP/IP and MS client installed as does the server. The Win 95's have a DNS server specified (which is back at the home office network). The Win 95's can't ping the 772 router even thou they are connected directly to the same hub as the NT server. The Win 95's can ping each other and the NT Server, but not the 772 router? WHY??????

Sometimes, after I reboot the router a couple times, all of the sudden the Win 95 pc's can ping it and get back to the home office network?
Now, the NT server can always always see the router and the home office network regardless of whether the 772 router is rebooted or not. It seems to me I have a win95/772 router issue, but what. Any helps would be great. [sig][/sig]

 

[jeter]

Very Odd !!! I'm sure you checked this already , however is the gateway of the 9 pc's
the same ip as the router ? What is your subnet mask ?
it sounds like its a Gateway issue , but thats what we have to elimate first .
Also just wondering what type of Hub/NICs do you have ? [sig][/sig]

 

[KFCColonel]

I solved the problem above. As it turns out, the router, a Cisco 772 has a software version (C760-in.b.US 4.3(1)) that only allows four mac addresses in its arp table. When rebooted, the router grabs the first four mac addresses that ping it. This explains the intermittent connectivity I explained above. The NT server just happened to always be running so it always grabbed one spot in the arp table. That meant only three spots in the arp table were left for three more PC's. Any PC's trying to ping the router after the arp table was full got denied. The "b" in the above software version indicates a four users license. I upgraded to software version C760-in.r.US 4.3(1) The "r" stands for remote office license which allows up to 1500 mac's in the arp table. VIOLA...problem solved! [sig][/sig]

 

[jeter]

Great job ! I'm sure that many of the subscribers here just learned a thing or two. [sig][/sig]