Time To Live is a mechanism to prevent messages from traversing the network indefinitely

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3
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2answers
37 views

Best CNAME TTL strategy for fallover switching

I've recently been thinking about the TTL of our DNS. We have A records for our servers and then CNAME records for the customer facing names. The www CNAME points to server-01 for example. In the ...
1
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2answers
32 views

Bouncing email due to bad initial MX TTL?

Last Friday night we changed mail servers. We moved off Office 365 to another hosted Exchange Solution (Intermedia.net). We use Godaddy for DNS, and after the server migration stuff was ready and ...
3
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0answers
51 views

Big Trouble with (I think) Outlook X500 addressing

I moved a small client from one hosted Exchange server (Microsoft Office 365) to another (Intermedia.net). Some emails from External senders to the users on the new server host are undeliverable, ...
0
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1answer
38 views

Setting DNS TTL for an external address

To start with, I don't know jack about DNS servers. I have been stuck with resolving a problem with a DNS-Server because I discovered a problem with one of our systems and determined that it was ...
12
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2answers
383 views

What happens when your TTL gets screwed up in your DNS record?

What happens when someone gets access to your DNS control and sets a TTL of 100 years on your domain, while pointing it's IP to some obscure website? (and you discover it too late of course)
0
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1answer
51 views

CDN and TTL on local EC2 files

I Have a file in CDN and I need a local copy of it in all of my EC2 instances. I like to set a TTL on the local copy of 5 minute, and have one of the following: Have it Fetch automatically as soon ...
2
votes
1answer
366 views

AWS Route 53 alias-record change takes too long

I have setup a stack in AWS Cloudformation, which is up and running. The stack contains an ELB (load balancer) and a few EC2-instances. When we do a new deployment of our application, we build a new ...
0
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1answer
68 views

Lowering TTL on nameserver, not registrar, then changing nameservers?

A client website has their domain name registered at GoDaddy. This domain points to Wix.com's nameservers. I've lowered the TTL in wix to 1 hour. However, when we go live we'll be switching the ...
3
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1answer
372 views

Outlook.com DNS so slow, postfix times out

I'm trying to send e-mails to for example: postmaster@grassvalley.com and postmaster@jorssen.net.bmw.be. In both cases these are Outlook mailboxes. Postfix replies with: (when ipv6 enabled): ...
0
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2answers
583 views

Change DNS TTL for every records in a zone

I have a forward lookup zone with a lot of A records. If I change the TTL for the zone, it does not apply to records (they keep the previous TTL setting). I have to manually change the TTL for every ...
1
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2answers
151 views

Is low TTL an appreciable burden on DNS?

I currently work for an medium-sized institution whose DNS management is questionable at best. Often, there are DNS-related failures causing downtime for the entire building and our public-facing ...
2
votes
3answers
198 views

DNS Nameserver updates affected by TTL? or is it just A records, MX etc?

The TTL has been set to 1H, so that IP changes for example.com can be made more quickly. The registrar has been configured with ns1.example.com and ns2.example.com, verified using WHOIS lookup. ns1 ...
3
votes
2answers
94 views

Will MX records with a longer TTL help mitigate effects of DoS attack?

We have our email hosted at Google Apps, and have our DNS servers for the domain setup at Namecheap. About a month ago our website went down (not a big deal, since it's most just a contact info ...
-1
votes
1answer
59 views

TTL on DNS for domains as a security measure [closed]

Ever since I read this article the other day, I've felt a bit uncomfortable about my domains being stolen. And I've tried taking each measure possible. But one I don't understand completely is TTL. ...
0
votes
1answer
909 views

Multiple $TTL statements in bind DNS zone file

I'm using a socks proxy to connect to servers using another application. The proxy, which runs on Solaris 10. The server hosting the proxy is configured to use our own internal DNS server (bind) to ...
0
votes
1answer
442 views

ICMP echo-reply packets with a much lower TTL (-190) than ICMP time-exceeded packets

When I ping the last three hops of a traceroute path to facebook.com from my location, the ICMP echo-reply packets I get back all have a TTL of respectively 58, 57 and 56. The hops in question are the ...
1
vote
1answer
102 views

bind9; how to automatically refresh entry after entry expires

I am looking for a way to automatically refresh entries in my cache if it expires. For example, example.com has a TTL of 60, i would like to automatically refresh it if it expires so that when users ...
0
votes
1answer
70 views

Fun this TTLs and many records in PDNS

I got very strange issue for me. I have powerdns server with potentially thousands of cname records. This records inserted to my DNS via mysql queries from network http service. This is a way how I ...
2
votes
1answer
162 views

Will setting my DNS TTL to 86400 prevent minor DNS outages from making my site unavailable?

This morning, Network Solutions (where we host our DNS) had some intermittent DNS Server outages. All of our sites were inaccessible during this time. When network solutions DNS Servers came back up, ...
0
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2answers
231 views

How long does azure cdn live before updating

I am using the windows Azure CDN, And not like Amazon's one cannot configure any TTL regarding the files, I was wondering if there is any official document microsoft had regarding to the ...
1
vote
1answer
354 views

How to actually set max-age headers on Windows Server?

I've set the max age to 1 minute, but when I look at the response headers, I see max-age=86400 (one day). Is something else overriding this setting? I've also set the kernel cache to 1 minute for ...
4
votes
1answer
756 views

How do I set a varnish response TTL dynamically?

my php script is sending a header X_Cache_ttl: 1h and in my varnish config file I have sub vcl_fetch { if(beresp.http.X-Cache-ttl){ set beresp.ttl = beresp.http.X-Cache-ttl; } } ...
8
votes
1answer
1k views

How does Varnish deal with running out of storage?

I am using Varnish 3.0.3 (the latest as of this writing) with more or less the default install, using the following for storage: # # Cache file location ...
2
votes
5answers
406 views

Generating ICMP packets when TTL=2?

By inspecting the payload of ICMP time-exceeded packets, I noticed that sometimes it is the last but one router (when ttl=2 in the returned packet) or even a previous one(up to 5 hops before, ttl=5) ...
-2
votes
4answers
216 views

Reducing TTL in DNS

What stops us from reducing the TTL of all DNS entries to 1 minute or something less? If that is done we won't have to wait mych for DNS changes to propagate so what all things force us to not do ...
1
vote
2answers
119 views

Understanding how Tracert works

From what I gathered so far, Tracert works by sending 3 ICMP echo messages. Starting with a TTL value of 1. For each router the packet encounters, the TTL value will be decremented. For the 1st ...
0
votes
1answer
124 views

Can't change serials in my SOA without breaking my nameservers

So I was testing my DNS using http://www.intodns.com/mydomain.com And it gave me a warning about the serials of my two nameservers not matching. So I changed the serials to match and restarted bind ...
0
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2answers
868 views

Optimizing TTL values for DYNDNS service

I've finally gotten my own DYNDNS working but I am looking for some advice on optimizing it. Edit: Basiclly I got a Domain at a registrar that I point to my own nameservers where I keep my own ...
1
vote
1answer
336 views

TTL and traceroute showing different values for same domain

Why am I getting two different outputs for tracert and ping? Ping Result showing total hops of 20 and tracert showing 8. Default ttl value on my Linux machine 64, icmp echo reply ttl value 44. ...
0
votes
1answer
510 views

Variable TTL inside a LAN

I recently discovered that ping my local router, returns different TTL values​​. The ping 3 switch must pass through before reaching the router, there may be the problem? 192.168.1.99 is the IP of my ...
1
vote
0answers
316 views

Squid 3.1: external_acl_type ttl won't work

I have custom script for handling Squid3's external_acl_type and it works fine. In this script (btw, its PHP) I turned on logging every request into the file. As far as I know from docs TTL value ...
4
votes
2answers
423 views

Windows Server 2008 R2 DNS - Syncronizing changes to TTL

I apologize if this has been asked. My searches have not been successful. If I have 2 DNS servers in my Domain and add an A record to 1 server, that record is successfully propagated to the second ...
5
votes
2answers
1k views

My TTL changing over every packetand I don't know why

Recently I discovered that some pings sent to me were giving a TTL error. When someone pings my computer, it shows a different TTL value for every packet. For example, ping.eu shows that: --- PING ...
3
votes
1answer
888 views

What DNS Settings to use to migrate Domain from One Server to Another

I am going to migrate a site from one server to another. The site has a good bit of realtime transaction activity reading/writing to a backend database. I believe I should ratchet down the TTL in the ...
11
votes
2answers
9k views

Varnish Cache - default TTL?

I have discovered that I can set the TTL in Varnish as follows in my VCL file: sub vcl_fetch { # 1 minute set obj.ttl = 1m; } But what is the default setting (assuming the backend server is ...
6
votes
2answers
5k views

What are the benefits of a high TTL for DNS?

I'm moving a domain's nameservers from the registrar to dnsmadeasy.com so that we can have automatic failover (among other benefits). When I've done this in the past I simply set the TTL value as low ...
0
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2answers
165 views

Can I find out whether my DNS provider honor my TTL settting?

Is there any way to determine if my DNS provider actually use the TTL setting I provide?
3
votes
1answer
7k views

Can Windows 2008 R2 DNS set TTL per record?

The DNS Manager administrative tool doesn't seem to have an option for configuring TTL for an individual record. I can set the TTL per-zone by right-clicking -> Properties -> SOA. Where is the ...
7
votes
5answers
967 views

Weighted round robins via TTL - possible?

I currently use DNS round robin for load balancing, which works great. The records look like this (I have a TTL of 120 seconds) ;; ANSWER SECTION: orion.2x.to. 116 IN A 80.237.201.41 ...
0
votes
3answers
115 views

BIND result validity

I setup a local name server (BIND on OS-X) and was pleased that 'dig' response times were very short (2nd query onwards). However, if I wait a short period (5s) the response time goes up again - the ...
0
votes
1answer
196 views

Added a third DNS Resolver and pulled a DNS A record… now inaccessible from certain parts of the world?

Here's a step-by-step rundown of my end-of-week nightmare: -Nov 8 @ 2am: One of our two internet providers began experiencing problems. Packets were being dropped and connectivity for our clients ...
3
votes
2answers
1k views

How network devices affect TTL

When I do a ping, I can see the TTL value for each packet. For every router that I insert in between my computer and the router that connects to the internet, the TTL value goes down by one. However, ...
6
votes
1answer
9k views

What does the TTL on a CNAME record mean?

Due to how many servers are involved in my network, I have a hard time keeping them all organized. Some of them don't have static IP's, so I thought it might be nice if I made a config.mydomain.com ...
0
votes
1answer
1k views

Cisco 3560+ipservices — IGMP snooping issue with TTL=1

I've got a C3560 with Enhanced (IPSERVICES) image, routing multicast between its VLANs with no external multicast router. It's serving a test environment where developers may generate multicast ...
9
votes
2answers
4k views

Any disadvantage to short DNS TTL? [closed]

Any disadvantage to short DNS TTL?
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vote
2answers
3k views

Differences of the TTL value in Tracert and Ping

When I ping localhost on my Windows XP system, the TTL value returned is 128 and it shows me that the default TTL value in the ping for my system is 128. Then when I ping google.com the returned TTL ...
1
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2answers
215 views

traceroute command details

As I see in wikipedia, traceroute utility sends a sequence of packets using ICMP protocol in groups of three and with incrementing TTL value to identify the network routers. It also says that Internet ...
2
votes
3answers
2k views

Using a low TTL to help prevent extended periods of downtime

Is it feasible to set my domain's TTL to a very low value (a couple of minutes) so that, if my main host goes down for an extended period of time, I can update the DNS records in my main host to point ...
39
votes
4answers
53k views

How can I see Time-to-live (TTL) for a DNS record?

I would like to see the Time-to-live (TTL) value for a CNAME record. I have access to dig (on Apple Leopard), which gives me an answer like this: % dig host.example.gov <*SNIP*> ;; ANSWER ...
0
votes
2answers
849 views

DNS TTL problem

So I have an external network card and an internal NIC on my windows 2008 R2 server. When I try to connect to some websites, i get a timeout which is a TTL problem. It goes away when i disable the ...