[CentOS] Slow login to system without internet connection

Ljubomir Ljubojevic office at plnet.rs
Tue Nov 20 18:48:40 UTC 2012


On 11/20/2012 07:34 PM, m.roth at 5-cent.us wrote:
> Ljubomir Ljubojevic wrote:
>> Hi.
>>
>> For a long time I am puzzled why, when internet connection is gone
>> (beyond first router, outside of subnet) SSH (and telnet?) connection is
>> drastically slowed.
>>
>> Same behavior, but less impacted is observed when system boots without
>> working internet connection, and I am not sure, but I think even access
>> to SAMBA fileshares can be/is affected. Affected systems are mostly
>> production servers, and too spaced apart in time to be able to point a
>> finger in something I am doing wrong.
>>
>> I have not had time to gather more facts, I always forget/don;t have
>> time, so I will only focus on definite SSH issue on CentOS 6.3, although
>> I have seen same with 5.x.
> <snip>
> Have you tried traceroute to a well-known location, like google.com, and
> seen where the delay is?
>
>       mark
>

Let me make it more clear.

I have a small WISP. I get my internet connection vai several wireless 
links/towers. My main server is located in my house. My own PC and the 
Server in question (in the example) are separated by a router in my 
house (different subnets). Server is fresh install of CentOS 6.3, all 
updated.

Now, when there was power failure (works on the transformer there), I 
lost my internet connection, but router and wireless routers for the 
rest of my towers were accessible. SSH logins to any of them is instant.

But when I tried to login to my server, it was not instantenous, and I 
think it was 15+, maybe even 30+ seconds (I forgot to time it) from 
start of ssh command to password prompt. It is in-house connection, so 
there is nothing to traceroute.



Past experience was, separate from this example, that a CentOS 5.x 
server in one company slows access, temporary timeout to SAMBA file 
server when wireless router connecting them to internet is turned off, 
although they are in local lan with static IP's.

-- 

Ljubomir Ljubojevic
(Love is in the Air)
PL Computers
Serbia, Europe

Google is the Mother, Google is the Father, and traceroute is your
trusty Spiderman...
StarOS, Mikrotik and CentOS/RHEL/Linux consultant


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