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

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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 ...
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2answers
84 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
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3answers
52 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 ...
2
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2answers
64 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 ...
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1answer
39 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
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1answer
170 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
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1answer
125 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
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1answer
60 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
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1answer
43 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
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1answer
101 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
84 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
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1answer
130 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 ...
3
votes
1answer
330 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
532 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
359 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
159 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
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2answers
104 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
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1answer
113 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 ...
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2answers
457 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
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1answer
238 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
342 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
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0answers
207 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
271 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
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2answers
824 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
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1answer
620 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 ...
7
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2answers
6k 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 ...
2
votes
2answers
3k 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
147 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?
2
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1answer
4k 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
667 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
98 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
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1answer
186 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
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2answers
695 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, ...
4
votes
1answer
6k 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
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1answer
968 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 ...
7
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2answers
3k views

Any disadvantage to short DNS TTL? [closed]

Any disadvantage to short DNS TTL?
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2answers
2k 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 ...
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2answers
209 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 ...
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4answers
41k 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
838 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 ...
1
vote
1answer
188 views

hightraffic dns ttl record

Whats bestpratice TTL for hightraffic www sites? Should there be a high TTL to make dnsservers around cache longer so the dnsserver wont have to get requests to often?
0
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4answers
579 views

ICMP - TTL - Trace Route

I asked this question at Stack Overflow and then thought this may be the better place to ask. Given the following situation: PC --- |aa RTR1 bb| --- |aa RTR2 bb| --- |aa RTR3 bb| etc Each of the ...
6
votes
3answers
4k views

CNAME and A record have different TTLs. Which one will be cached?

If a CNAME has a TTL of 1 hour that points to an A record with a TTL of 1 minute, will someone who looks up this CNAME have the entire result cached for 1 hour, or will it will keep having to lookup ...
5
votes
1answer
2k views

Small TTL values

What is a TTL in DNS? What is the advantage of having small TTL?
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2answers
384 views

DDNS + DHCPD : Once lease runs out, does DNS entry get removed?

Once there are several hundred adhoc machines being brought up, each with a unique name. Their hostname gets added to the DNS. Then upon TTL expiring, will the DNS entry still be reachable, or if the ...
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3answers
3k views

What percentage of nameservers honor TTL these days?

Some years ago I had to do several DNS changes over the course of several weeks as I moved bits of equipment from one data center to the other. At the time that I did this, about 95% of the ...
19
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2answers
28k views

Recommended DNS SOA record TTL default?

We currently have our DNS SOA record set to the following for stackoverflow.com: primary name server = ns1.p19.dynect.net serial = 2009090909 refresh = 3600 (1 hour) retry = 600 ...
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3answers
722 views

What DNS piece of information do I need to change if I'm going to be moving servers soon?

I'm going to be moving servers for our website soon. Instead of having a long period of 'downtime' for clients because their DNS client is caching the entries for a 'long time', can I hint to the DNS ...
2
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2answers
1k views

Recommend a content delivery network (CDN) for a specific purpose [closed]

could you please recommend a CDN for the following use: 1) Ability to update files on the edge servers automatically through API, so it should take no more than 5-10 minutes to make a new version of ...