eigrp issue

[d7425]

I have a Lan . In the lan there are a 3600 router and seven 1750 router .I use eigrp protocol on ethernet interface .And i use the eigrp authentication md5. In these router ,the 3600 ios is 12.2(2)t, some 1750 router ios is 12.2(8)y8.otehr 1750 ios is 12.1(3)xt1. but the 3600 lost some neighbor . but i cancel the authentication ,everything is good. why ?

[thisisshanky]

There are numerous bugs related to EIGRP md5 authentication. The solution is to either turn of authentication or to upgrade the code to a bug free code. 12.2(2)T is an IOS affected with one such bug. with bug ID CSCdw84055. You might want to upgrade the code on all IOSes to a bug free one.